All Saints Polish National Church is located at 1020 Grant Street. Per Houses of Worship, it was originally part of a larger congregation at Holy Mother of the Rosary on Sobieski Street. Citing distance, a new congregation established their own Polish language church at 189 Grote Street (now residential) in 1929 in order to worship in the area in which they lived.
In 1953 they built the church on Grant Street, and are the only remaining PNC church in the City of Buffalo.
They still hold regular services there, meeting also on Sunday afternoons, which I figured out when photographing the cornerstone.