In the title compound, 3C(10)H(8)N(2)·4C(7)H(5)NO(4), the asymmetric unit contains two mol-ecules of pyridine-3,5-dicarb-oxy-lic acid and one mol-ecule of 4,4'-bipyridine in general positions together with one mol-ecule of 4,4'-bipyridine lying across a centre of inversion, thus giving a 4:3 molar ratio of pyridine-3,5-dicarb-oxy-lic acid to 4,4'-bipyridine. The dihedral angle between the bipyridine rings on general positions is 21.2 (2)°. These mol-ecular units are linked by O-H⋯N hydrogen bonds forming an extended two-dimensional framework in the crystal.