Bononia, once the residential episcopal see of the city of Bononia (now Vidin) in Bulgaria, is a titular see of the Catholic Church.
The city of Bononia lay within the ancient Roman province of Dacia Ripensis. Under its present name of Vidin, it is part of Bulgaria.
It was important enough to become a suffragan bishopric of the Metropolitan Archbishop of the provincial capital Raziaria. The Latin adjective by which the diocese is referred to is Bononiensis.
The diocese was nominally restored in 1933 as Latin Catholic titular bishopric of Bononia (Latin = Curiate Italian) / Bononien(sis) (Latin adjective).
It has had the following incumbents, so far of the fitting Episcopal (lowest) rank :