I’ve passed this building countless times and always take a beat, never knowing its purpose or history. It wasn’t hard to dig up information about what used to the first official library building at the University of Cincinnati that opened in 1901. Prior to this date the collection was strewn about classrooms at the University Building on McMicken Avenue. This and more info from The History of University Libraries — a 16 page PDF about all the libraries at UC.
The dome was added during extensive renovations in 2006. It’s no longer a library but serves as administrative offices.