10,11,12,13-Tetrahydro-4,5,9,14-tetraazadibenz[a,c]anthracene–benzene-1,4-dicarboxylic acid (2/1)

In the title adduct, 2C18H14N4·C8H6O4, the centrosymmetric 1,4-benzenedicarboxylic acid molecule makes two O—H...·N hydrogen bonds to adjacent 10,11,12,13-tetrahydro-4,5,9,14-tetraazadibenzo[a,c]anthracene (TTBT) molecules. Aromatic π–π stacking interactions occur between TTBT rings [centroid–centroid distance = 3.570 (3) ], leading to a two-dimensional supramolecular structure in the crystal.