Officers believe he could hold important information about the two incidents, the first of which happened on Friday, April 28.
It was reported that a man entered a lift in a building on Arundel Street at about 2.40pm and indecently exposing himself to a woman
Another woman reported seeing a man indecently exposing himself while using a lift at a car park in Eyre Street at about 4.15pm on Tuesday, May 2.
South Yorkshire Police said today that officers investigating the two incidents believe that the same man was involved.
Anyone with information about either of the incidents or who recognises the man pictured is asked to call police on 101, quoting incident number 869 of 2 May 2017.
Alternatively, call Crimestoppers anonymously on 0800 555 111.