Hello Aspirant,

Yes both these are different colleges . Indian Institute of Science or IISc offers UG , PG and research course in their campus . There are various courses offered in IISc like

Division of Biological Sciences.

Division of Chemical Sciences.

Division of Physical and Mathematical Sciences.

Division of Electrical Sciences.

Division of Mechanical Sciences.

Division of Interdisciplinary Research etc.

Where talking about Indian Institute of Astrophysics or IIA mainly focuses and offers integrated courses like M.Tech with PhD like-

M.Tech + Ph.D in Astronomical Instruction.

M.Tech. + Ph.D. in Physics

M.Tech. + Ph.D. in Astrophysics

Hopes this helps.

All the best!