He breathed his last at Dhaka's Islami Bank Central Hospital around 3 pm on Monday, said Ahsan Habib Nasim, general secretary of Abhinaya Shilpi Sangha.
Inamul was suffering from heart disease, according to Nasim.
He leaves behind his wife Lucky Inam, a fellow actor and director, and their daughters Hridi Haque and Proiti Haque. His sons-in-law Litu Anam and Saju Khadem are also actors.
Inamul was rushed to the hospital by Litu and actor Shahid Alamgir, who lives in the same building when he suddenly fell ill after lunch at home.
Lucky alerted the others after noticing that Inamul was unresponsive while resting after the meal, said Shahid. Inamul was then taken to the hospital, where doctors later declared him dead.
The family has not made a decision on his funeral service.
Born in Feni on May 29, 1943, Inamul graduated from Dhaka University’s chemistry department. He did a PhD research at Manchester University in the UK as well.
He had worked as the head of Bangladesh University of Engineering and Technology’s chemistry department for a long time.
He began his journey as a thespian while studying at Notre Dame College. Inamul founded Nagorik Natyasampraday theatre group in 1968. In 1995, he left the group and formed Nagorik Natyangan.
Besides theatre, Inamul also worked in TV. His wife Lucky is currently the chairman of Shishu Academy.