Butane-1,2,3,4-tetra-carboxylic acid-4,4'-bipyridine (1/2).

The hydro-thermal reaction of butane-1,2,3,4-tetra-carboxylic acid (H(4)butca), 4,4'-bipyridine (bipy) and Mn(SO(4))(2)·H(2)O afforded a new co-crystal, C(8)H(10)O(8)·2C(10)H(8)N(2) or H(4)butca·2(bipy), in which strong O-H⋯N hydrogen-bonding and weak π-π stacking [centroid-centroid distance = 3.8459 (19) Å] inter-actions assemble the organic mol-ecules into a three-dimensional supra-molecular framework. C-H⋯O inter-actions are also present. The whole mol-ecule has inversion symmetry.