I think most of the Bengali songs I know are by Salil Chowdhury just because there are Malayalam versions for them that I'm familiar with, too.
But this one, "Ei poth jodi na sesh hoi," isn't by him, at least not as far as I know. It's a romantic song from the West Bengali movie
Saptapadi (1961):
https://www.youtube.com/watch?v=dPErEox2hws