In the title ortho-rhom-bic polymorph (space group 2), CHN, the dihedral angle between the benzene rings is 55.99 (10)° and the azepine ring adopts a boat conformation. In the crystal, mol-ecules are linked by C-H⋯π contacts. The previously-reported polymorph [Yousuf (2012 ▶). . E, o1101] crystallizes in the monoclinic system (space group 2/) with two mol-ecules in the asymmetric unit.