is iisc banglore for engineering
No IISC is a research institutions so there you can't do engineering course .
But it has some M. Tech Degrees in civil engineering and aerospace engineering
Yes IISC Bangalore is also for engineering but it is more research oriented. It is one of top best Institutes in India. Also it has world ranking of around 301-400.
Admission to it are done through KVPY which is one of the toughest exams in engineering section.
https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.kvpy.iisc.ernet.in/&ved=2ahUKEwimk-eF8PXhAhWWaCsKHdKbCZ0QFjAAegQIAhAB&usg=AOvVaw16Y6WxXkRwTRJmYoXVLxCe
Can i join this through jee main
Please read the official page for details about spot admission and respective cutoffs.
https://www.iisc.ac.in/ug/news.html