Developer Thomas O’Brien of Boston-based HYM Investments is proposing a 69-story, 780-foot-tall residential tower that would become the city’s second-tallest building, just 10 feet shy of the Hancock Tower.

O’Brien was one of eight developers who submitted proposals to build a skyscraper in the Financial District. The Boston Redevelopment Authority sought proposals for a one-acre parcel currently occupied by the municipal garage at 115 Winthrop Square.

O’Brien’s plan calls for a substantial redevelopment of the square, including a new Boston public school and a relocated St. Anthony Shrine, friary and ministry center. Under the O’Brien proposal, the church properties and school would be built on the former garage site and a residential tower with 11,000-square-foot floor plates would be built on the former shrine property.

Trans National’s Steve Belkin, who was the only bidder on a similar project during the Menino administration, proposed a 1.5-million-square-foot mixed-use development including office space, condos and apartments. Belkin would combine the city-owned property with his 133 Federal St. site next-door, increasing the development site which would include a 740-foot tower.

Other developers submitting proposals include The Fallon Co., Lincoln Property Co., Lend Lease Development in a partnership with Hudson Group, Millennium Partners, Trinity Financial and Accordia Partners.

The submissions will be reviewed by staff at the city’s Economic Development Industrial Corp. and the next step could be a more detailed request for proposals.