It is a handsome building, that does indeed have neoclassical lines. I hope that it is being restored for loving use.

[link from AADL] says:
First Church of Christ, Scientist, 1913

This building was originally the home of the First Church of Christ, Scientist. Its members first organized as a society in 1900, and re-organized into a church in 1901. Services were held in a rented home on this site which the church eventually bought. They removed the house and laid the cornerstone for this church building in 1912. It was opened to the public in 1913 and officially dedicated in June of 1926, free from debt.

The church is designed in a neo-classical style, somewhat reminiscent of Monticello, the home of Thomas Jefferson, whose models for classicism came from the Romans rather than the Greeks. The architect was Spencer Solon Beman, son of Chicago architect Solon Spencer Beman, who is famous for his design of Pullman, a planned community in Chicago.

Helen Aminoff wrote a very interesting history of the Jews in Ann Arbor, through the early 20th century. You can find it here: [link]
Emily Rose followed up with a different summary of the earliest residents (with pictures!): [link]

Based on what I read (I just re-read Helen Aminoff’s piece), I don’t think it was once a synagogue, but maybe I missed something. I believe the first actual synagogue in Ann Arbor (as opposed to meeting in people’s homes) was where the current Hillel building is now. Osias Zwerdling wanted to make sure that Jewish students could access the location.