I am trying to make an app using the Unity game engine while referencing a library compiled with .NET 4.0. I've noticed that every time I open the project in the Unity Editor, it switches the framework on my Visual Studio solution from 4.0 back to 3.5, so my referenced library is no longer usable. I do not need the functionality of the Unity Editor, I am willing to write my entire program in C# scripts if possible. Is it possible to make a .NET 4.0 project without using the Unity Editor? 99% of my code is in C# scripts, but it seems like I still need to have a game object in the Unity Editor with my main script attached to it in order for the Unity window to open. Is there a way for me to write a script that makes this first game object for me so I never have to open the Unity Editor? If I do open it then my framework is changed back to .NET 3.5 and I cannot use my .NET 4.0 library. I am running Visual Studio 2013 Professional and Unity Editor 4.3.4 on Windows 8.1 with the Windows 8.1 SDK installed. Thanks for any help!