Abstract
A new ortho-rhom-bic polymorph of the title compound, C30H24N4, with a density of 1.315 Mg m(-3), has been obtained. The mol-ecule is centrosymmetric with the centroid of the cyclo-hexa-1,4-diene ring located on an inversion center. The two unique benzene rings are almost perpendicular to each other [dihedral angle = 86.70 (6)°] and are oriented at dihedral angles of 30.79 (5) and 68.07 (5)° with respect to the central cyclo-hexa-diene ring. In the crystal, π-π stacking is observed between the central cyclo-hexa-1,4-diene-1,4-di-amine unit and a phenyl ring of a neighboring mol-ecule [centroid-centroid distance = 3.7043 (7) Å]. The crystal structure of the triclinic polymorph [Ohno et al. (2014 ▶). Acta Cryst. E70, o303-o304] showed chains running along the b-axis direction through weak C-H⋯π inter-actions.