Abstract
The asymmetric unit of the title 1:1 co-crystal, C10H8N2·C10H10O4, consists of one half-mol-ecule each of 4,4'-bi-pyridine and 1,4-phenyl-enedi-acetic acid: the complete mol-ecules are generated by crystallographic inversion centres. The dihedral angle between the -CO2H group and the benzene ring in the diacid is 73.02 (7)°. In the crystal, the components are linked by O-H⋯N hydrogen bonds, generating [1-2-1] chains of alternating amine and carb-oxy-lic acid mol-ecules. The chains are cross-linked by C-H⋯O inter-actions. This structure was previously incorrectly described as a (C10H10N2)(2+)·(C10H8O4)(2-) mol-ecular salt [Jia et al. (2009 ▸). Acta Cryst. E65, o2490-o2490].