2-Phenyl­acetic acid–(E,E)-4,4’-(hydra­zinediylidene)dipyridine (2/1)

The asymmetric unit of the title co-crystal, C(12)H(10)N(4)·2C(8)H(8)O(2), comprises a single mol­ecule of 2-phenyl­acetic acid and half a mol­ecule of 4-pyridine­aldazine as this is situated about a centre of inversion. Mol­ecules are connected into a three component aggregate via O—H⋯N hydrogen bonds. As the carb­oxy­lic acid group is almost normal to the plane through the benzene ring to which it is attached [C—C—C—C = 93.7 (3) °], and the 4-pyridine­aldazine mol­ecule is planar (r.m.s. deviation of the 16 non-H atoms = 0.010 Å), the overall shape of the aggregate is that of an extended chair. In the crystal packing, layers of three component aggregates stack along the c axis.