Third Party 'Newtonsoft' type or namespace could not be found.. (Unity 5 / PUN / VS2010)

I would like to use the 'PUN' with 'UNITY 5'.
but I have a problem.

Under point, an error occurs.

PhotonNetwork/AccountService.cs
using Newtonsoft.Json;
error : 'Newtonsoft' type or namespace could not be found..

Newtonsoft.Json.dll are contained within PhotonNetwork folder.

Windows 7 64bit
Unity 5
PUN
VS2010 / .Net Framework 3.5

please help me..

 

Cause was because I did not add the dll files in the project settings. T.T

 

Hello,
I am also facing the same problem.
I have

1. Created a Unity Project
   
   
2. Imported PUN in Assets/Plugin folder of the Project
   
   
3. Getting error that " error CS0246: The type or namespace name `Newtonsoft' could not be found." But I have checked in ../Editor/PhotonNetwork/, there is Newtonsoft.jason.dll and I also checked in Program Files/Unity/MonoDevelop/bin folder..there is also Newtonsoft.jason.dll is existing.
   

It would be very kind If anyone clearly show me the steps of the solution.

I am using free version of Unity and PUN. I am using Operating System : Windows 8.1 (64 bit)

Can You tell me how you did it? Please

 

If you go to run/attach to process -> choose Unity -> and then run the project in Unity. You should be able to debug the project when you run it. Regardless the Json error