diff --git a/src/ReleaseHistory.md b/src/ReleaseHistory.md
index 8727b6b61..025caacc2 100644
--- a/src/ReleaseHistory.md
+++ b/src/ReleaseHistory.md
@@ -1,6 +1,8 @@
 # SARIF Package Release History (SDK, Driver, Converters, and Multitool)
 
 ## Unreleased
+
+* BUGFIX: Fix `ArgumentNullException` when `PropertiesDictionary` is instantiated with a null comparer. [#2482](https://github.com/microsoft/sarif-sdk/pull/2482)
 * BUGFIX: Fix `UnhandledEngineException` when target path does not exist for multithreaded application by validating directories as is done for singlethreaded analysis. [#2461](https://github.com/microsoft/sarif-sdk/pull/2461)
 
 ## **v2.4.14** [Sdk](https://www.nuget.org/packages/Sarif.Sdk/2.4.14) | [Driver](https://www.nuget.org/packages/Sarif.Driver/2.4.14) | [Converters](https://www.nuget.org/packages/Sarif.Converters/2.4.14) | [Multitool](https://www.nuget.org/packages/Sarif.Multitool/2.4.14) | [Multitool Library](https://www.nuget.org/packages/Sarif.Multitool.Library/2.4.14)
diff --git a/src/Sarif/TypedPropertiesDictionary.cs b/src/Sarif/TypedPropertiesDictionary.cs
index 344c2a4c0..964761a3f 100644
--- a/src/Sarif/TypedPropertiesDictionary.cs
+++ b/src/Sarif/TypedPropertiesDictionary.cs
@@ -19,7 +19,7 @@ public TypedPropertiesDictionary() : this(null, StringComparer.Ordinal)
         {
         }
 
-        public TypedPropertiesDictionary(PropertiesDictionary initializer, IEqualityComparer<string> comparer) : base(comparer)
+        public TypedPropertiesDictionary(PropertiesDictionary initializer, IEqualityComparer<string> comparer) : base(comparer ?? StringComparer.Ordinal)
         {
             if (initializer != null)
             {
diff --git a/src/Test.UnitTests.Sarif.WorkItems/Test.UnitTests.Sarif.WorkItems.csproj b/src/Test.UnitTests.Sarif.WorkItems/Test.UnitTests.Sarif.WorkItems.csproj
index 735d42194..25539bf41 100644
--- a/src/Test.UnitTests.Sarif.WorkItems/Test.UnitTests.Sarif.WorkItems.csproj
+++ b/src/Test.UnitTests.Sarif.WorkItems/Test.UnitTests.Sarif.WorkItems.csproj
@@ -9,6 +9,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks Condition="$(OS) == 'Windows_NT'">$(TargetFrameworks);net48</TargetFrameworks>
     <IsPackable>false</IsPackable>
     <IsTestProject>true</IsTestProject>
     <RootNamespace>Test.UnitTests.Sarif.WorkItems</RootNamespace>
diff --git a/src/Test.UnitTests.Sarif/PropertiesDictionaryTests.cs b/src/Test.UnitTests.Sarif/PropertiesDictionaryTests.cs
index 241fbc29d..6d58afc04 100644
--- a/src/Test.UnitTests.Sarif/PropertiesDictionaryTests.cs
+++ b/src/Test.UnitTests.Sarif/PropertiesDictionaryTests.cs
@@ -172,6 +172,24 @@ public void PropertiesDictionary_TestCacheDescription()
             PropertiesDictionary_TestCacheDescription_Helper(GeneratePropertiesDictionaryProperty, PROPERTIES_NONDEFAULT);
         }
 
+        [Fact]
+        public void PropertiesDictionary_ShouldNotThrownException_WhenComparerIsNull()
+        {
+            var initializer = new PropertiesDictionary();
+
+            Exception exception = Record.Exception(() =>
+            {
+                new PropertiesDictionary(initializer);
+            });
+            exception.Should().BeNull();
+
+            exception = Record.Exception(() =>
+            {
+                new PropertiesDictionary(initializer, comparer: null);
+            });
+            exception.Should().BeNull();
+        }
+
         private void PropertiesDictionary_TestCacheDescription_Helper(Func<int, string, IOption> GeneratePropertyMethod, object value)
         {
             string textLoaded = string.Empty;
diff --git a/src/Test.UnitTests.WorkItems/Test.UnitTests.WorkItems.csproj b/src/Test.UnitTests.WorkItems/Test.UnitTests.WorkItems.csproj
index fdabcaa80..4f6b691c0 100644
--- a/src/Test.UnitTests.WorkItems/Test.UnitTests.WorkItems.csproj
+++ b/src/Test.UnitTests.WorkItems/Test.UnitTests.WorkItems.csproj
@@ -10,6 +10,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks Condition="$(OS) == 'Windows_NT'">$(TargetFrameworks);net48</TargetFrameworks>
     <IsPackable>false</IsPackable>
     <IsTestProject>true</IsTestProject>
   </PropertyGroup>