A 24-year-year old man was punched in an unprovoked attack inside Rush late bar, in Clumber Street, Mansfield.
The incident happened at around at 2.30am on 19 July.
Police believe the man in the image may be able to assist with their investigation.
PC Damon Shaw, of Nottinghamshire Police, said: “This was an unprovoked attack that left the victim with a nasty cut above his left eye that required stitches.
“As part of the ongoing investigation we are eager to speak to the man pictured and would urge anyone who recognises him, or who may have information which can help, to get in touch.”
Those with information are asked to call 101, quoting incident number 86 of 19 July.
Alternatively, information can be reported anonymously to the independent charity Crimestoppers on 0800 555 111.