Though there are many coffee shops plus eateries on baner road as well as pashan road but all close bit early.
If you are a bit late to decide (say post 11 PM) yet want to grab your coffee mug as well as want someting to munch on; Cafe Coffee Day which is centrally located near kapil malhar on baner road is the safest and highly recommended bet.
I was in a similar situation. Thankfully they were open and full of young crowd at even 11:20 PM.
Though I am not a CCD buff yet at this time of night you dont have many options either.
Standard CCD ambiance with tables inside as well as a few outside, nice location.
Coffee and pastry or say a piece of cake under Rs 200; decent way to finish the day. Good enough.