diff --git a/src/Chr.Avro/Abstract/RecordSchemaBuilderCase.cs b/src/Chr.Avro/Abstract/RecordSchemaBuilderCase.cs
index 968699b2d..633694240 100644
--- a/src/Chr.Avro/Abstract/RecordSchemaBuilderCase.cs
+++ b/src/Chr.Avro/Abstract/RecordSchemaBuilderCase.cs
@@ -9,10 +9,11 @@ namespace Chr.Avro.Abstract
     using System.Runtime.Serialization;
     using System.Text.RegularExpressions;
     using Chr.Avro.Infrastructure;
+    #if !NET6_0_OR_GREATER
     using NullabilityInfoContext = Chr.Avro.Infrastructure.NullabilityInfoContext;
     using NullabilityState = Chr.Avro.Infrastructure.NullabilityState;
     using NullabilityInfo = Chr.Avro.Infrastructure.NullabilityInfo;
-
+    #endif
 
     /// <summary>
     /// Implements a <see cref="SchemaBuilder" /> case that matches any non-array or non-primitive
diff --git a/src/Chr.Avro/Infrastructure/NullabilityInfo.cs b/src/Chr.Avro/Infrastructure/NullabilityInfo.cs
index 379866cc0..2f4ea2401 100644
--- a/src/Chr.Avro/Infrastructure/NullabilityInfo.cs
+++ b/src/Chr.Avro/Infrastructure/NullabilityInfo.cs
@@ -1,3 +1,4 @@
+#if !NET6_0_OR_GREATER
 namespace Chr.Avro.Infrastructure
 {
     using System;
@@ -70,3 +71,4 @@ internal NullabilityInfo(
         public NullabilityInfo[] GenericTypeArguments { get; }
     }
 }
+#endif
diff --git a/src/Chr.Avro/Infrastructure/NullabilityInfoContext.cs b/src/Chr.Avro/Infrastructure/NullabilityInfoContext.cs
index 461a56f0e..e64d21879 100644
--- a/src/Chr.Avro/Infrastructure/NullabilityInfoContext.cs
+++ b/src/Chr.Avro/Infrastructure/NullabilityInfoContext.cs
@@ -1,3 +1,4 @@
+#if !NET6_0_OR_GREATER
 namespace Chr.Avro.Infrastructure
 {
     using System;
@@ -572,3 +573,4 @@ public bool ParseNullableState(int index, ref NullabilityState state)
         }
     }
 }
+#endif
diff --git a/src/Chr.Avro/Infrastructure/NullabilityState.cs b/src/Chr.Avro/Infrastructure/NullabilityState.cs
index 1f16f316d..1b83737a6 100644
--- a/src/Chr.Avro/Infrastructure/NullabilityState.cs
+++ b/src/Chr.Avro/Infrastructure/NullabilityState.cs
@@ -1,3 +1,4 @@
+#if !NET6_0_OR_GREATER
 namespace Chr.Avro.Infrastructure
 {
     /// <summary>
@@ -26,3 +27,4 @@ internal enum NullabilityState
         Nullable,
     }
 }
+#endif