In the crystal structure of the title compound, [Cu3(C12H7N2O)2Cl2]n, the mixed‐valence CuI/CuII cation and the cuprate(I) anion both lie on centres of inversion. The O atom of one half of the planar N,N′‐chelated dinuclear copper cation binds to the Cu atom of the other half; the geometry around the metal atom is square‐planar, owing to the symmetry‐related metal atom at a distance of 2.3945 (5) Å. The dinuclear cations are bridged through the anions to form an infinite linear chain.