From the Home page of NotepadPlusPlusPluginPack.Net
References The prefered way to use dependencies is via References, in the best-case through NuGet. Via NuGet you are able to add packages to your project, certain versions etc. through a global repository. Package information is stored in your project and other developers can gather the same, correct versions through the global repository without committing masses of data. To use included references in your compiled plugin you need to merge these into the .dll as Notepad++ is not fond of locating non-plugin .dll's in its folder. ILMerge was developed for the purpose of merging managed libraries. It can be installed via NuGet and used manually. The best way is to install MSBuild.ILMerge.Task via NuGet in your plugin project. It will include ILMerge as dependency and attach itself to your Visual Studio build process. By that, with every build you compile a merged plugin .dll including all your custom references to use. ILMerge will add configuration files to your project: ILMerge.props and ILMergeOrder.txt. Refer to the official homepage for more information about the configuration possibilities. Note: To use ILMerge in your plugin you have to change the Target Framework of your plugin project to at least .NET Framework 4.0 (CP). ILMerge can work with .NET 3.5 and below, but requires additional configuration and adaptation. If you do not required the extreme backwards compatibility, upgrade the .NET Framework target as quick and easy solution.