By the 1940s, the church was thriving and numbered 2400 members, but in the years following World War II, members moved away and dropped to fewer than 100. In 1982, the church, faced with a $9,000 winter heating bill and dwindling membership, the congregation accepted an offer from a developer to convert the church and chapel into luxury apartments.
In a New York Times article “Church Makes Novel Deal with Developer,” dated December 5, 1982, the church’s pastor, the Rev. Neville-Simmons Smith said, ''As you can see, we cannot maintain the building with our meager resources. The plaster has cracked on the wall behind the pulpit, and the old stained-glass windows along the south wall are broken and chipped.”
After the 1851 Romanesque-style church was sold, the congregation worshiped in the former Ladies’ Parlor behind the church. Fortunately, the church complex had just been granted landmark status by the city’s Landmarks Preservation Commission in the spring of 1982, so the church’s exterior could not be architecturally altered.
Reporting why the New York Landmarks Conservancy approved the conversion of the church, its Executive Director Laurie Beckelman wrote in The State of Churches report, “The proposal for the church is innovative in that it enables the congregation to remain within the church complex and continue to serve the immediate community. While plans for the interior call for the retention of as much of the original building fabric as possible, the creation of three residential floor levels will dramatically alter the scale and sense of the original interior space.”
In 1993, the small congregation, lead by Rev. Smith, merged with Plymouth Church in Brooklyn Heights, and in a sad way brought the story of the relationship of South Congregational Church and Plymouth Church to a full circle.