2-[(4-Hydroxy­phen­yl)diazen­yl]benzoic acid–N,N′-bis­(4-pyridylmeth­yl)oxamide (2/1)

The asymmetric unit of the title co-crystal, 2C(13)H(10)N(2)O(3)·C(14)H(14)N(4)O(2), comprises one mol­ecule of 2-(4-hydroxy­phenyl­diazen­yl)benzoic acid and half of an N,N′-bis­(4-pyridylmeth­yl)oxamide mol­ecule as the latter is disposed about an inversion centre. The most notable feature of the crystal structure is the formation of supra­molecular chains arising from hydr­oxy–pyridine O—H⋯N contacts and amide–hydr­oxy C—H⋯O contacts. These give rise to 40-membered {⋯OH⋯NNC(4)OH⋯NC(4)NC(2)NH}(2) synthons, generating supra­molecular chains along [01[Image: see text]]. The chains are connected into a two-dimensional array via C—H⋯π inter­actions. Layers, with a step-ladder topology, are consolidated into the crystal structure via further C—H⋯π inter­actions.