Supra­molecular aggregation in three 4-aryl-6-(1H-indol-3-yl)-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitriles

Both 6-(1H-indol-3-yl)-3-methyl-4-(4-methyl­phen­yl)-1-phen­yl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile and 6-(1H-indol-3-yl)-3-methyl-4-(4-methoxy­phen­yl)-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile crystallize from dimethyl­formamide solutions as stoichiometric 1:1 solvates, viz. C₂₉H₂₁N₅·C₃H₇NO, (I), and C₂₉H₂₁N₅O·C₃H₇NO, (II), respectively; however, 6-(1H-indol-3-yl)-3-methyl-1-phenyl-4-(3,4,5-trimethoxy­phen­yl)-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile, C₃₁H₂₅N₅O₃, (III), crystallizes in the unsolvated form. The heterocyclic components of (I) are linked by C—H...π(arene) hydrogen bonds to form cyclic centrosymmetric dimers, from which the solvent mol­ecules are pendent, linked by N—H...O hydrogen bonds. In (II), the heterocyclic components are linked by a combination of C—H...N and C—H...π(arene) hydrogen bonds into chains containing two types of centrosymmetric ring, and the pendent solvent mol­ecules are linked to these chains by N—H...O hydrogen bonds. Mol­ecules of (III) are linked into simple C(12) chains by an N—H...O hydrogen bond, and these chains are weakly linked into pairs by an aromatic π–π stacking inter­action.