After the fire of 1872 that destroyed much of downtown Boston, there was a new concern for fireproof buildings and new building codes. Buildings with their cast-iron fronts acting as a curtain wall for brick structures represent one architectural response. Only five cast-iron fronts survive in Boston, though many more were constructed. Cast iron was believed to be fireproof, though that was later disproved.
Cast-iron construction also has the advantage of enabling efficient construction, and the Citizens Bank Building was one of the first new buildings to open after the fire. The date of construction is visible on the third story. Originally the building held dry goods merchants. Nearby at 71–73 Summer Street, original cast-iron work from the same period, designed by George W. Pope, can be seen in the stories above the modernized ground and second floors.