[5] He was the first person to hoist the Flag of Bangladesh on 2 March 1971 as the vice president of Dhaka University Central Students' Union.

Under the leadership of Chhatra League leader Noor Alam Siddiqui, Abdul Kuddus, A S M Abdur Rab and Shajahan Siraj, the flag of independent Bangladesh was hoisted in Dhaka University on 2 March 1971.

In the historic Bot-tala of Dhaka University, A S M Abdur Rab handed over the flag of Bangladesh to Sheikh Mujibur Rahman.

After the independence of Bangladesh, Rab formed the left-wing Jatiya Samajtantrik Dal (National Socialist Party).

President Abu Sadat Mohammad Sayem released M. A. Jalil and Abdur Rab after taking power because of the involvement of Jatiya Samajtantrik Dal in the coup d'état in November 1975.