N-[2-(Benzylideneamino)phenyl]-N?-phenylurea

In the title compound, C20H17N3O [systematic name: 1-phenyl-3-{2-[(E)- (phenyl­methyl­idene)amino]­phen­yl}urea], the middle benzene ring forms dihedral angles of 17.65?(17) and 29.48?(14)°, respectively, with the N- and C-bound phenyl rings, while the dihedral angle between the terminal rings is 46.53?(18)°. In the crystal, mol­ecules are linked via N—H...O hydrogen bonds, forming helical supra­molecular chains running parallel to the c axis via an R12(6) ring motif. The structure was refined as a two-component twin with a 0.966?(3):0.034?(3) domain ratio.