The murder was perpetrated near CDRI in Hazratganj, when Bachchan had gone out for a morning stroll on Sunday. After firing shots at him, the assailants reportedly fled the spot.
This is the first major crime in the state capital after the police commissionerate system was implemented in Lucknow on January 14.
It is reported that Bachchan was out on morning walk with his brother at Globe Park in Hazratganj. In the incident, while Bachchan died on spot, his brother received bullet injuries. He has been admitted to Trauma Centre of the King George's Medical University (KGMU) where he is being treated for his injuries.
Watch | Hindu leader shot dead in Lucknow's Hazratganj
On receiving information, senior officials of police reached the spot immediately and sent the body of the deceased Hindu leader for post-mortem. A probe has been initiated by police.
Reacting to the incident, Samajwadi Party sought resignation from the Yogi government, and questioned the government over the rise in criminal incidents in the state.
Ranjit Bachchan lived in the OCR building and belonged to Gorakhpur.
This is the second murder of a Hindu leader in the state capital in the past four months. Kamlesh Tiwari, president of the Hindu Samaj Party, was shot dead in his office on October 18 by two assailants who had befriended him by creating a fake Facebook ID.