Abstract
In the crystal of the title 1:1 adduct, C(8)H(7)ClO(2)·C(12)H(10)N(4), the components are linked by an O-H⋯N hydrogen bond between the carb-oxy-lic acid and one of the pyridine N atoms. In the acid, the carb-oxy-lic acid group is approximately normal to [dihedral angle = 72.9 (2)°] but twisted with respect to the plane through the benzene ring [C-C-C-O torsion angle = 25.4 (5)°]. The base is roughly planar [dihedral angle between rings = 12.66 (15)°; r.m.s. deviation of the 16 non-H atoms = 0.107 Å] and the conformations about both imine bonds are E. The dimeric aggregates are linked into a supra-molecular layer in the ab plane by C-H⋯O inter-actions.