Benzoic acid-4-{(1E)-[(E)-2-(pyridin-4-yl-methyl-idene)hydrazin-1-yl-idene]meth-yl}pyridine (2/1).

In the title co-crystal, C(12)H(10)N(4)·2C(7)H(6)O(2), the complete 4-pyridine-aldazine mol-ecule is generated by a crystallographic centre of inversion. In the crystal, mol-ecules are connected into a three component aggregate via O-H⋯N hydrogen bonds. As both the benzoic acid [O-C-C-C torsion angle = 174.8 (2)°] and 4-pyridine-aldazine (r.m.s. deviation of the 16 non-H atoms = 0.041 Å) mol-ecules are almost planar, the resulting three-component aggregate is essentially planar. The crystal packing comprises layers of the three-component aggregates of alternating orientation stacked along the b axis; the connections between the mol-ecules are of the types C-H⋯π and π-π [pyridine-benzene centroid-centroid distance = 3.787 (4) Å].