The Grade II listed building, on Deiniol Road, is listed with Auction House North Wales and is set to go to auction on October 2 with a guide price of £700,000.
Described by the auction agent as a “truly iconic and unique period building”, it was built in 1909.
Once the main Counters District Office for Royal Mail of North Wales, the site remained a post office until 2008, when the post office was moved to Bangor High Street.
MORE: Anti-social behaviour takes its toll at Wood Fired Shack
Shortly after, it became the ‘Embassy’ and ‘Revive’ nightclub, but has been empty for several years.
According to the agents, the main building has had plans put in place but not yet submitted to be developed into a bar, restaurant and club complex as well as a private medical centre.
They added: “The scope this building offers is huge, (subject to planning) it could be an apartment complex, student accommodation, hotel, office space and much, much more.”