c# - Unable to use JSON -

i have attempted use json.net, installed via nuget , tried include project using using statement. it's not showing in list of namespaces.

i decided go asp.net web api libraries has json support. again tried include using using statement, no namespace. though it's installed.

using system.json; 

also tired

using system.net.json; 

i'm using c# 5 , .net 4.5. how can 1 of these packages work? stated both installed via nuget. there's no namespace them showing in intellisense.

the namespace looking is:

using newtonsoft.json;