diff --git a/lib/Conversion/DCToHW/DCToHW.cpp b/lib/Conversion/DCToHW/DCToHW.cpp
index ef0da21d7153..fb57dd7f1051 100644
--- a/lib/Conversion/DCToHW/DCToHW.cpp
+++ b/lib/Conversion/DCToHW/DCToHW.cpp
@@ -118,7 +118,9 @@ class ESITypeConverter : public TypeConverter {
           if (inputs.size() != 1)
             return std::nullopt;
 
-          return inputs[0];
+          return builder
+              .create<UnrealizedConversionCastOp>(loc, resultType, inputs[0])
+              ->getResult(0);
         });
 
     addSourceMaterialization(
@@ -128,7 +130,9 @@ class ESITypeConverter : public TypeConverter {
           if (inputs.size() != 1)
             return std::nullopt;
 
-          return inputs[0];
+          return builder
+              .create<UnrealizedConversionCastOp>(loc, resultType, inputs[0])
+              ->getResult(0);
         });
   }
 };
diff --git a/lib/Conversion/HWArithToHW/HWArithToHW.cpp b/lib/Conversion/HWArithToHW/HWArithToHW.cpp
index bd7c4ca7a7c5..65349b1fc93a 100644
--- a/lib/Conversion/HWArithToHW/HWArithToHW.cpp
+++ b/lib/Conversion/HWArithToHW/HWArithToHW.cpp
@@ -393,7 +393,9 @@ HWArithToHWTypeConverter::HWArithToHWTypeConverter() {
           mlir::Location loc) -> std::optional<mlir::Value> {
         if (inputs.size() != 1)
           return std::nullopt;
-        return inputs[0];
+        return builder
+            .create<UnrealizedConversionCastOp>(loc, resultType, inputs[0])
+            ->getResult(0);
       });
 
   addSourceMaterialization(
@@ -402,7 +404,9 @@ HWArithToHWTypeConverter::HWArithToHWTypeConverter() {
           mlir::Location loc) -> std::optional<mlir::Value> {
         if (inputs.size() != 1)
           return std::nullopt;
-        return inputs[0];
+        return builder
+            .create<UnrealizedConversionCastOp>(loc, resultType, inputs[0])
+            ->getResult(0);
       });
 }
 
diff --git a/lib/Conversion/HandshakeToDC/HandshakeToDC.cpp b/lib/Conversion/HandshakeToDC/HandshakeToDC.cpp
index cbc0171eb317..e6b6a4f0213f 100644
--- a/lib/Conversion/HandshakeToDC/HandshakeToDC.cpp
+++ b/lib/Conversion/HandshakeToDC/HandshakeToDC.cpp
@@ -92,7 +92,9 @@ class DCTypeConverter : public TypeConverter {
           if (vt && !vt.getInnerType())
             return pack(builder, inputs.front());
 
-          return inputs[0];
+          return builder
+              .create<UnrealizedConversionCastOp>(loc, resultType, inputs[0])
+              ->getResult(0);
         });
 
     addSourceMaterialization(
@@ -112,7 +114,9 @@ class DCTypeConverter : public TypeConverter {
           if (vt && !vt.getInnerType())
             return pack(builder, inputs.front());
 
-          return inputs[0];
+          return builder
+              .create<UnrealizedConversionCastOp>(loc, resultType, inputs[0])
+              ->getResult(0);
         });
   }
 };
diff --git a/lib/Conversion/HandshakeToHW/HandshakeToHW.cpp b/lib/Conversion/HandshakeToHW/HandshakeToHW.cpp
index 37cfd483fa6e..b4b883606fb9 100644
--- a/lib/Conversion/HandshakeToHW/HandshakeToHW.cpp
+++ b/lib/Conversion/HandshakeToHW/HandshakeToHW.cpp
@@ -71,7 +71,9 @@ class ESITypeConverter : public TypeConverter {
             mlir::Location loc) -> std::optional<mlir::Value> {
           if (inputs.size() != 1)
             return std::nullopt;
-          return inputs[0];
+          return builder
+              .create<UnrealizedConversionCastOp>(loc, resultType, inputs[0])
+              ->getResult(0);
         });
 
     addSourceMaterialization(
@@ -80,7 +82,9 @@ class ESITypeConverter : public TypeConverter {
             mlir::Location loc) -> std::optional<mlir::Value> {
           if (inputs.size() != 1)
             return std::nullopt;
-          return inputs[0];
+          return builder
+              .create<UnrealizedConversionCastOp>(loc, resultType, inputs[0])
+              ->getResult(0);
         });
   }
 };
diff --git a/lib/Conversion/LTLToCore/LTLToCore.cpp b/lib/Conversion/LTLToCore/LTLToCore.cpp
index b6482ac3e19a..4e0a7df05f22 100644
--- a/lib/Conversion/LTLToCore/LTLToCore.cpp
+++ b/lib/Conversion/LTLToCore/LTLToCore.cpp
@@ -138,7 +138,9 @@ void LowerLTLToCorePass::runOnOperation() {
           mlir::Location loc) -> std::optional<mlir::Value> {
         if (inputs.size() != 1)
           return std::nullopt;
-        return inputs[0];
+        return builder
+            .create<UnrealizedConversionCastOp>(loc, resultType, inputs[0])
+            ->getResult(0);
       });
 
   converter.addSourceMaterialization(
@@ -147,7 +149,9 @@ void LowerLTLToCorePass::runOnOperation() {
           mlir::Location loc) -> std::optional<mlir::Value> {
         if (inputs.size() != 1)
           return std::nullopt;
-        return inputs[0];
+        return builder
+            .create<UnrealizedConversionCastOp>(loc, resultType, inputs[0])
+            ->getResult(0);
       });
 
   // Create the operation rewrite patters
diff --git a/lib/Conversion/MooreToCore/MooreToCore.cpp b/lib/Conversion/MooreToCore/MooreToCore.cpp
index 323a4287f75b..ee581c63347d 100644
--- a/lib/Conversion/MooreToCore/MooreToCore.cpp
+++ b/lib/Conversion/MooreToCore/MooreToCore.cpp
@@ -1301,7 +1301,9 @@ static void populateTypeConversion(TypeConverter &typeConverter) {
           mlir::Location loc) -> std::optional<mlir::Value> {
         if (inputs.size() != 1)
           return std::nullopt;
-        return inputs[0];
+        return builder
+            .create<UnrealizedConversionCastOp>(loc, resultType, inputs[0])
+            ->getResult(0);
       });
 }
 
diff --git a/lib/Conversion/SeqToSV/SeqToSV.cpp b/lib/Conversion/SeqToSV/SeqToSV.cpp
index d4a13ea369fe..dd3931dc6eb5 100644
--- a/lib/Conversion/SeqToSV/SeqToSV.cpp
+++ b/lib/Conversion/SeqToSV/SeqToSV.cpp
@@ -363,7 +363,10 @@ struct SeqToSVTypeConverter : public TypeConverter {
             mlir::Location loc) -> std::optional<mlir::Value> {
           if (inputs.size() != 1)
             return std::nullopt;
-          return inputs[0];
+          return builder
+              .create<mlir::UnrealizedConversionCastOp>(loc, resultType,
+                                                        inputs[0])
+              ->getResult(0);
         });
 
     addSourceMaterialization(
@@ -372,7 +375,10 @@ struct SeqToSVTypeConverter : public TypeConverter {
             mlir::Location loc) -> std::optional<mlir::Value> {
           if (inputs.size() != 1)
             return std::nullopt;
-          return inputs[0];
+          return builder
+              .create<mlir::UnrealizedConversionCastOp>(loc, resultType,
+                                                        inputs[0])
+              ->getResult(0);
         });
   }
 };
diff --git a/lib/Dialect/FIRRTL/Transforms/LowerClasses.cpp b/lib/Dialect/FIRRTL/Transforms/LowerClasses.cpp
index a36b25f170ff..d77f52c73972 100644
--- a/lib/Dialect/FIRRTL/Transforms/LowerClasses.cpp
+++ b/lib/Dialect/FIRRTL/Transforms/LowerClasses.cpp
@@ -1849,18 +1849,22 @@ static void populateTypeConverter(TypeConverter &converter) {
   converter.addConversion(
       [](DoubleType type) { return FloatType::getF64(type.getContext()); });
 
-  // Add a target materialization to fold away unrealized conversion casts.
+  // Add a target materialization such that the conversion does not fail when a
+  // type conversion could not be reconciled automatically by the framework.
   converter.addTargetMaterialization(
       [](OpBuilder &builder, Type type, ValueRange values, Location loc) {
         assert(values.size() == 1);
-        return values[0];
+        return builder.create<UnrealizedConversionCastOp>(loc, type, values[0])
+            ->getResult(0);
       });
 
-  // Add a source materialization to fold away unrealized conversion casts.
+  // Add a source materialization such that the conversion does not fail when a
+  // type conversion could not be reconciled automatically by the framework.
   converter.addSourceMaterialization(
       [](OpBuilder &builder, Type type, ValueRange values, Location loc) {
         assert(values.size() == 1);
-        return values[0];
+        return builder.create<UnrealizedConversionCastOp>(loc, type, values[0])
+            ->getResult(0);
       });
 }