Throughout the 19th century, the library continued to struggle with membership levels because of its increasing conservatism ( at one time even excluding students from Queen’s College and debating whether or not to include works of fiction). As it approached its 100th anniversary, the library lost its “permanent” premises in order to make way for the construction of a new City Hall. It eventually moved to a warehouse (previously used for storing linen) further down Donnegall Street. During this period, the Society’s membership became increasingly ambitious in regards to its collection of books and began to develop cultural programs.
Following World War II, and then through the decades of “The Troubles,” membership again began to decline. By 1980, proposals were being made to permanently close the library. The public came to the library’s rescue with an earnest effort to save it, which proved successful. A fund raiser was established to renovate and update the building, with construction commencing in 1999 and completion on September 16, 2000.