If you want to include assemblies conditionally upon its preprocessor from c# project, you can use Condition keyword. See the following snippet. xx.csproj <Reference Condition=" $(DefineConstants.Contains('XXX_LIB_OS')) " Include="DRVNAME1, Version=1.1.1.0, Culture=neutral, PublicKeyToken=xxxxx, processorArchitecture=AMD64"> ... </Reference> <Reference Condition=" $(DefineConstants.Contains('XXX_LIB_APP')) " Include="APPNAME1, Version=1.1.1.0, Culture=neutral, PublicKeyToken=xxxxxxx, processorArchitecture=AMD64"> ... </Reference> Then define the constant <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x86'"> <DebugSymbols>true</DebugSymbols> <OutputPath> ... … Continue reading C# Conditional assembly reference →