The asymmetric unit of the title compound, [Cu(CHO(2))Cl(C(5)H(8)N(2))(3)](2)·[CuCl(2)(C(5)H(8)N(2))(2)] or 2[A]·[B], contains one A mol-ecule and one half-molecule of B, located on a centre of inversion. The Cu(II) environments in A and B are different. In A, the Cu(II) atom is coordinated by three N atoms from three 3,5-dimethyl-1H-pyrazole (L) ligands, one O atom from a formate ligand and a chloride anion in an axial position [Cu-Cl = 2.4275 (7) Å] in a distorted tetra-gonal-pyramidal geometry. The Cu(II) atom in B is coordinated by two N atoms from two L ligands and two chloride anions [Cu-Cl = 2.2524 (6) Å] in a distorted square-planar geometry. In the crystal, inter-molecular N-H⋯O hydrogen bonds link mol-ecules A into centrosymmetric dimers. Inter-molecular N-H⋯Cl hydrogen bonds further link these dimers with the B mol-ecules, forming chains propagating in [101].