Conformational dimorphism of 2,2'-methyl-enebis(isoindoline-1,3-dione).

In this study, a new monoclinic polymorph (space group C2/c) of 2,2'-methyl-enebis(isoindoline-1,3-dione), C17H10N2O4, is reported and compared to the previously reported triclinic polymorph (space group P ). Similarly, both polymorphs consist of a unique mol-ecule in the asymmetric unit (Z' = 1). The mol-ecular conformations of the two polymorphs are very similar, as shown by the r.m.s. deviation of 0.368 Å (excluding all H atoms). The inter-molecular inter-actions of both polymorphs are described along with the Hirshfeld surface analysis, and the lattice energies are calculated.