The veteran leader has vowed to take "sanyas" from politics in protest.
"I had proposed names of a reputed lawyer for the Hooghly seat and another person for Arambagh constituency. But I find that the names of both have not been cleared and instead others have been chosen," Mannan told PTI.
Mannan, who has been with Congress for nearly 50 years and was the chairman of WBPCC media cell, said, "I will leave politics. I will not join any other party, but will not be here anymore either."
Chowdhury, also a Minister of State for Railways, was unavailable for comment.