The 69-year-old leader was admitted to the hospital here three days ago. He was shifted to ICU last evening and was declared dead at 6.20 AM today.
His mortal remains will be flown to Dimapur later today and cremation will take place there tomorrow, family sources said.
"He was admitted to AIIMS three days ago with heart ailment and his condition worsened last evening, following which he was shifted to ICU," a senior doctor at AIIMS said.
An active social worker who strived for the uplift of weaker sections and downtrodden, Zhimomi represented the state of Nagaland in the Rajya Sabha, which was adjourned for the day as a mark of respect to the departed leader.
He was a Rajya Sabha member for two terms - from July 2008 to April 2010 and from April 2010 till his demise today.
He was first elected to the Nagaland Legislative Assembly in 1989 and served as MLA for three terms from 1989 to 1992, from 1993 to 1997 and from 2003 to 2008.
He also served as Cabinet Minister in charge of Industries and Commerce in the Nagaland People's Council Government headed by Chief Minister Vamuzo in 1990.
Zhimomi was chairman of Zhimomi Group Of Industries (ZGI) and had business interests in a number of sectors.
Born on February 19, 1946, in Nagaland, he leaves behind seven daughters and two sons.
He was a student leader and founding member of Nagaland Students' Federation.
His eldest daughter is married to former Nagaland Chief Minister and the lone Lok Sabha member from the state Nephiu Rio.
Parliamentary Affairs Venkaiah Naidu along with Ministers of State Jitender Singh and Kiren Rijiju visited AIIMS and paid floral tributes to Zhimomi.
Condoling Zhimomi's demise, Nagaland Chief Minister T R Zeliang, in a condolence message, described him as the "most colourful and popular politicians of the state".
"He had been a very powerful personality and had always been a fatherly figure to the government. His zeal and determination to serve the people was intense and he seemed to have an inexhaustible amount of energy when it came to rendering his services to the people, the party and the government," Zeliang said.
"It is glaringly obvious that the void his demise has caused in the political firmament of the Naga politics can never be filled again," the CM said.
Zeliang also prayed for the Almighty to grant solace and comfort to his wife, Khezheli Zhomomi and family in this hour of grief as well as eternal peace to the departed soul.