The building was refurbished in 1778 converting some of the storage space into a theatre: the Accademia dei Solleciti Theatre. It was a popular theatre, their plays using vernacular and starring Stenterello – the Florentine character at Carnival – as well as operas and tragedies. In 1866 the name was changed to honour the composer Gioacchino Rossini, and it became the Rossini Theatre. It remained as such until 1877, when the Chief of Police ordered its closure for reasons of safety.

The premises were turned into a storage room or book deposit for the Gabinetto Vieusseux (The Vieusseux Cabinet), until 1895 when it was purchased by the British Baptist Mission. In 1908 the building underwent major renovation to turn it into a hall of worship under engineer Vittorio Tarchiani: for instance, the proscenium or apron stage was turned into an apse with a semi-octagonal plan in neo-Renaissance style. The only vestige of the old use of the building can be seen in the traces of a gallery that replaces the theatre boxes.