Two polymorphs of ,'-diphenyl-2-[1-(propyl-amino)-ethyl-idene]propanedi-amide.

Two polymorphs of the title compound, CHNO, have been isolated. Polymorph () crystallizes in the monoclinic space group / and polymorph () in the tetra-gonal space group /. The main difference between the two polymorphs on the mol-ecular level is the orientation of the -propyl group. This group is anti-periplanar in () and synclinal in (). The core of the mol-ecule consists of two carbamoyl units bound to an enamine unit. The most prominent features are intra-molecular N-H⋯O hydrogen bonds in both polymorphs. Both polymorphs form dimers with graph set (12) inter-molecular N-H⋯O hydrogen bonds. Adjacent dimers of () are connected a weak C-H⋯O inter-action, resulting in a chain parallel to the crystallographic -axis. The dimers of () are connected by weak C-H⋯π inter-actions, forming inter-molecular chains along the -axis direction.