c# generics dictionary (TKEY, TValue)

How can we achieve the dictionary (TKEY, TValue) functionality with other .NET features?

 

I am going to parse first two csv lines (headers,values) and then split them on base of comma ',' and then add them both parallel to the collection. I am able to do this with dictionary but when the two headers same or empty it gives error "n item with the same key has already been added in dictionary". In my case Tkey=First Line Header Values and TValue = Second Line Values.