How to marge to sp result in MVC???

Hello,

 

i am margeing two sp data in mvc....below code

 

 In my controller below code.......

 

 

 

var rs1 = db.sp_storeprocedure1(235).ToList();
var rs2 = db.sp_storeprocedure2(235).ToList();

var data = rs1.Concat(rs2); 

 

but show the error.....