The St. Vincent Street Church was built in 1859 to rehouse the Gordon Street United Presbyterian congregation. Alexander, along with his brother George, persuaded the churchgoers to sell them their former church, which was located where the Grosvenor Building is now on Gordon Street. With the profits of the sale, they built the new church.

However, the congregation dissolved in 1934 and may have fallen into similar disrepair as the Caledonia Road Church had it not been occupied by the Glasgow Association of Spiritualists. In the 1960s, it was bought over by the Glasgow City Council, and after much restorative work, it was granted a Category A listed status. Further restoration was needed in the late 1990s, funded by donations from the World Monuments Watch. It has been let to the Free Church of Scotland since 1971.

While it is believed to be a collaborative effort between the two brothers, the detailed design is clearly Alexander’s. The stone carving was carried out by John Mossman, who had worked with the firm on various projects in the past. Daniel Cottier, a favourite of Thomson, was responsible for the interior decoration. If Cottier’s name is familiar to you, it may be from the Cottier Theatre. Housed in the former Dowanhill Church designed by William Leiper, it too was decorated by Cottier, and was named after him when changing uses.