Dear Vijay,

If you want to get into IIT after doing Polytechnic course, then you will have to take up JEE Mains and JEE Advanced. Also, there are no lateral entries into IITs. Hence, you will get into the first year of the B.Tech course.

Diploma holders can get admitted into IITs only and not into NITs even if they crack these exams.

Hope this helps!