In the title compound, C19H14FNS2, the seven-membered thia-zepine ring adopts a slightly distorted twist boat conformation. The dihedral angle between the benzene rings is 53.6 (1)°. The mean plane of the thia-zepine ring is twisted by 34.3 (7)° and 36.6 (7)° from the benezene rings. A C-H⋯F interaction generates stacking of molecules along the ab plane.