The 71-year-old freedom fighter, who was a member of the first committee to formulate the Constitution, had been on life support at the Labaid Hospital in Dhaka.
The eloquent parliamentarian and witty public speaker was declared dead at 4:10am on Sunday, the hospital’s Chief Operating Officer Al Emran Chowdhury told bdnews24.com.
Suranjit, who has been suffering from a low haemoglobin count, was admitted to the hospital on Friday.
The seven-time lawmaker from Sunamganj was transferred to the hospital's Coronary Care Unit at 8pm on Saturday.
But the family, quoting doctors, told bdnews24.com that the condition of the veteran politician did not allow them to fly him abroad.
Sengupta was put on life support around 12:30am but that was removed around 4am.
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President Md Adbul Hamid and Prime Minister Sheikh Hasina have expressed their condolences over the death of the veteran Awami League leader. Finance Minister AMA Muhith has also issued a condolence statement.
Awami League General Secretary and Minister Obaidul Quader said his death has 'created a void' and it was an 'immeasurable loss.'
"He was a colourful personality in our political history. In my opinion, he is the Number One parliamentarian. His death has created a void," he told the media on Sunday at the hospital.
Suranjit, who was the one of the youngest members of the East Pakistan Provincial Assembly in 1970, has been an MP in almost of all of parliaments in the four decades of Bangladesh's independence.
The Awami League Advisory Council member began his political career as a left ideologue during the troubled 1960s.
His mortal remains were taken to his home at Dhaka's Jigatala around 9am, where Speaker Shirin Sharmin Chaudhury, Cabinet members AMA Muhith, Obaidul Quader, Rashed Khan Menon, Nurul Islam BSc, Chief Whip ASM Feroze, local MP Fazle Nur Tapash, Awami League leaders Hassan Mahmud, Khalid Mahmud Chowdhury came among others.
"He had played a vital role in drafting the Constitution. He had been vocal, even while serving as a minister, if anyone tried to attack the Parliament's independence," said Civil Aviation Minister Menon.
Suranjit, who has been a lawmaker since Bangladesh's birth in 1971, became a Cabinet member for the first time in 2011, but his short stint as a minister did not end well.
A life in politics, Parliament and government
Born in 1946 at Anwarapur in north-eastern Sunamganj district's Dirai Upazila, Suranjit Sengupta got involved in leftist politics in his early life and was elected a lawmaker seven times.
After completing his undergraduate and postgraduate degrees at the Dhaka University, he got his LLB at the Central Law College and practised law for some time.
Suranjit, who was involved with leftist student body 'Chhatra Union', hit the spotlight during the 1970 election when he was elected lawmaker from the National Awami Party (NAP) amid landslide victories of Awami League candidates across the country.
He took part in the 1971 Liberation War as a sub-commander of the Sector-5.
In 1979, he represented the 'Ekota Party' in the House and in 1991, the 'Ganatantri Party.'
Suranjit, who had attained national stature without representing any major political party, joined the Awami League in 1996, but lost the national election that year.
He, however, made to Parliament through a by-election.
Suranjit represented Sunamganj-2 constituency in the next three Parliaments, including the current Tenth Parliament. In 1996, then Prime Minister Sheikh Hasina made him her adviser for parliamentary affairs.
Suranjit, who sat on the first committee to draft the Constitution, was the co-chairman of the parliamentary panel over the Constitution's 15th Amendment during the Ninth National Parliament.
After Awami League's landslide victory in the 2008 polls, Suranjit along with other 'reformist' top Awami Leaguers were kept outside the government.
He had lost his post in the party's policymaking Presidium and was put on the apparently 'powerless' Advisory Council with other veteran leaders like, Tofail Ahmed, Amir Hossain Amu and late Abdur Razzaq.
Suranjit, who had been always witty public speaker, went on record then saying 'You can escape from a tiger's attack, but not when Sheikh Hasina strikes.'
Suranjit was given the portfolio of the newly-formed railways ministry, after which he had vowed to wipe out corruption from the public sector entity.
But within five months, he found himself in a soup, when his assistant personal secretary was arrested by police in possession of a huge amount of cash.
Suranjit rendered his resignation following the incident, but Hasina did not accept it and kept him as a minister without a portfolio.
But he did not make it in the Cabinet after the 2014 national polls. He served as the chairman of the Parliamentary Standing Committee for the Law, Justice and Parliamentary Affairs Ministry until he passed away on Sunday.