The two buildings were both listed on the National Register of Historic Places as part of the Two Bridges Historic District. Unfortunately, the National Register does not protect buildings as the city Landmarks Preservation Commission can. The owners filed in February for "minor alterations" with "no change of use, occupancy or egress." There is no filing for demolition at the Dept. of Buildings.
Justin Ferate, the renowned urban, social and architectural historian, supplies this photograph to give a better sense of the period (these are landmarked in Brooklyn Heights):
Zella Jones, founder of the NoHo Alliance, provides this recent photograph of 24 Henry, the older of the two buildings demolished:
For structures largely ignored for two centuries, they were in remarkably good shape, and because they eventually were surrounded by a slum -- part of New York's oldest slum -- they were neglected and so largely unaltered. But the neighborhood -- Henry, Madison and Monroe Streets around Catherine and Market Streets -- has seen newly built developments.