Mamoon mainly worked on the historical city of
Dhaka. He wrote several books about this city, took part in movements to protect Dhaka. Among his historical works on 1971 is his
Sei Sob Pakistani, in which many interviews with leading Pakistanis was published. Most of them were the leading Pakistani characters during the liberation war of Bangladesh. In 2009, Mamoon and General KM Safiullah filed a petition with the Bangladesh High Court asking it to direct the government to maintain the historic locations at
Suhrawardy Udyan and all over Bangladesh. Justices
A. B. M. Khairul Haque and
Md. Mamtaz Uddin Ahmed of the High Court Division issued a verdict in favor of the petitioners asking the government to preserve historical sites. He is the vice president of Ekatturer Ghatak Dalal Nirmul Committee, advocacy group for the trial of War Criminals of
Bangladesh Liberation War. In 2012, Mamoon appeared as a prosecution witness at International Crimes Tribunal-1 which was engaged by the Bangladesh Government to try the war criminals of 1971. In his witness's account, Mamoon said that members of the
Peace Committee used to advise Pakistani military leaders about where and how to strike the freedom fighters of Bangladesh. Mamoon is the Bangabandhu chair at the
University of Chittagong. He is the chairman of the trustee board of 1971: Genocide and Torture Archive and Museum in Khulna. == Criticism and lawsuits ==