President Pranab Mukherjee had rejected his mercy plea last year but Yakub's lawyer says that petition was filed by his family on his behalf.
The 53-year-old chartered accountant is to be hanged at a jail in Nagpur on Thursday for his role in the deadly terror attack in which 257 people were killed in blasts at various landmarks across Mumbai.
Yakub's last-ditch plea for mercy comes at a time the Supreme Court is still hearing his petition to stop his execution on grounds that proper procedure was not followed.
A two-judge bench yesterday differed on his petition.
Justice Anil Dave said Yakub's execution must not be stopped, quoting a Sanskrit shloka to say: "If the king doesn't punish the guilty with red eyes then the entire sin will come on the king."
Justice Kurien Joseph, however, said that there had been a clear violation of procedure and "such technicality should not stand in the way to protect the life of a person."
Yakub Memon has pleaded that the death warrant for his execution is illegal because it was issued before he had exhausted every legal option; his curative petition challenging the Supreme Court's ruling had not been heard then. It was rejected last week. His lawyers also said judges who ordered the death sentence should have been part of the bench that decided on the curative petition.
Of the 11 sentenced to death for the terror attack, Yakub was the only convict not granted mercy.
A group of eminent citizens, including politicians, jurists and retired judges, had also asked President Pranab Mukherjee to grant mercy to Yakub, arguing that in comparison, "the other 10 planted the bombs and played a much more critical and direct role."
Yakub's brother Tiger Memon, the main accused along with underworld don Dawood Ibrahim, has been missing since 1993.
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