1-[(E)-4-(Phenyl-diazen-yl)phen-yl]-3-pyrroline-2,5-dione.

The title compound, C(16)H(11)N(3)O(2), displays a trans configuration with respect to the azo group. The mol-ecule is non-planar; the maleimide ring forms a dihedral angle of 42.35†(4)° with the benzene ring bonded to its N atom and the mean plane of this benzene ring is rotated by 21.46†(8)° with respect to the azo group mean plane, which, in turn, forms a dihedral angle of 24.48†(7)° with the 'terminal' benzene ring. Mol-ecules in the crystal are π-π stacked along the [100] direction with a mean inter-planar distance of 3.857†(1)†à . In addition, C-H⋯O inter-actions link them into double layers parallel to the ac plane.