Like all colleges administered according to Statutes of University of Calcutta, SDBI( C ) has a democratically elected Students' Union. There is constructive relation between the union and college administration. Critical inputs are always welcome from the students' Union. The most notable aspect is that the Students' Union has had a tradition of contribution - physical and financial- for development of the college, be it donation for extension of the library in 1988 and 2004, or to the fund for commemoration of 50 years completion of the college.

The students' Union also organizes various cultural programs and competitions, like quiz, debate, extempore, music, indoor games, viz. carom, and chess apart from annual sports. It also publishes the annual college magazine. The Union activities are of social relevance, like organizing blood donation camp, health awareness campaign, awareness program and check-up camp for Thalassemia, campaign against Water pollution, awareness seminar to observe world Habitat Day, Woman's Day etc.