Two similarly substituted benzo[h]pyrazolo[3,4-b]quinoline-5,6(10H)-diones: supramolecular structures in two and three dimensions.

The molecules of 8-methyl-7,10-diphenyl-5H-benzo[h]pyrazolo[3,4-b]quinoline-5,6(10H)-dione, C(27)H(17)N(3)O(2), (I), are weakly linked into chains by a single C-H...O hydrogen bond, and these chains are linked into sheets by a pi-pi stacking interaction involving pyridyl and aryl rings. In 8-methyl-7-(4-methylphenyl)-10-phenyl-5H-benzo[h]pyrazolo[3,4-b]quinoline-5,6(10H)-dione, C(28)H(19)N(3)O(2), (II), the molecules are linked into a three-dimensional framework structure by a combination of C-H...N, C-H...O and C-H...pi(arene) hydrogen bonds, together with a pi-pi stacking interaction analogous to that in (I).