To b.com accounting and financial ke baad kya kare bank me job karne ke liye

Hi Deepak,
                   No it's not mandatory. Because students from different stream applied for the bank exams. If you have knowledge or you learn these things, you will get benefit in future. Because if you join any bank so your environment of work is surrounded by finance all the time.
So if you have time, then learn it. But when you are applying for higher posts, thru demand finance background.