A fire at 1051 Saratoga St. jumped to 1053 Saratoga before being brought under control, the Boston Fire Department reports.
Two firefighters were injured while battling the fire, reported at 12:53 a.m., the department says - one with heat exhaustion, one with a knee injury.
No residents were injured; 34 were displaced, the Red Cross says.
The department estimated damage at $500,000 for each building. Inspectors were called in to try to determine the cause of the fire.
Casey Leish captured the flames shooting into the sky: