T = 120 K; mean (C-C) = 0.002 A ˚; R factor = 0.031; wR factor = 0.108; data-to-parameter ratio = 12.4.In the title compound, C 17 H 18 F 2 N 2 O 2 , the imidazolidine ring system exists in a twist conformation.The mean plane through this ring system forms dihedral angles of 80.8 (8) and 66.2 (13) , with the benzene rings.The dihedral angle between the benzene rings is 52.0 (14) .Two intramolecular O-HÁ Á ÁN hydrogen bonds each generate S(6) ring motifs.In the crystal, weak C-HÁ Á ÁO hydrogen bonds form dimers, which are connected by further C-HÁ Á ÁO interactions.