Merchant had arranged the finance for the blasts, and was also linked to conspirators Tiger Memon and Dawood Ibrahim.
Tahir Merchant alias Tahir Takla, one of the convicts in the 1993 Mumbai blasts case who was sentenced to death, died at a hospital in Pune on Wednesday, a police official said.
Merchant, who was admitted to the Sassoon Hospital around 3 am after he complained of chest pain, died during treatment, the official said.
"One (1993 Mumbai blasts) convict named Tahir Merchant, who was lodged in the Yerawada prison, was admitted to Sassoon Hospital after he complained of chest pain. However, he died there during treatment around 3.45 am," Dr Bhushankumar Upadhyay, Additional Director General of Prisons Department said.
"Merchant was extradited to India from Abu Dhabi and was arrested by the Central Bureau of Investigation in 2010 and serving his jail term in Yerwada central prison in Pune," an official said.
According to police, Merchant had arranged the finance for the blasts, and was also linked to conspirators Tiger Memon and Dawood Ibrahim.
In 2007, a special TADA court had convicted 100 accused, including actor Sanjay Dutt, in connection with the blasts. In September last year, a special court awarded death sentence to Tahir Merchant and Firoz Khan, while awarding life imprisonment to prime accused Abu Salem and Karimullah Khan in the 1993 Mumbai blasts case.
The court had held that Merchant was amongst the main conspirators.
"The evidence proves the anguish, agitation and frustration expressed by Tahir due to situation prevailing in Bombay during the period of riots in January 1993," it had noted.
He worked with (absconding conspirator) Tiger Memon, participated in several conspiracy meetings in Dubai. Tahir made travel arrangements, financed the stay and travel of several co-accused and facilitated their training in Pakistan, the court noted.
"The role of Tahir in conspiracy is prominent. He is one of the initiators of the conspiracy," the court had said in its ruling in June 2017.
Another convict in the case, Mustafa Dossa had died of cardiac arrest at J J Hospital in Mumbai in June last year.
The Mumbai blasts had left 257 people dead and 713 seriously injured. It had destroyed properties worth Rs 27 crore.