3,5-Bis(aminomethyl)pyrazole (Hbampz) forms binuclear copper(II) complexes of the formula [Cu2(bampz)2X2] (X = CI, Br). The crystal structure of [Cu2(bampz)2Br2] has been determined by the X-ray method: formula = CuBrN4C5H9, monoclinic, space group P21/n, a = 9.214(1), b = 10.078(1), c = 8.775(1) Å, β = 97.33(1)°, V = 808.1 Å3. Two bampz- molecules combine with two copper(II) ions via the pyrazolate nitrogen and aminonitrogen atoms in the side chains affording an essentially planar N4 environment for each metal ion. The Cu-Cu separation is 3.947(5)A. The axial site of each copper is weakly coordinated by a bromide ion with a Cu-Br distance of 2.895(4) A. Cryomagnetic investigations over the temperature range 80-300 K revealed a significant antiferromagnetic interaction through the pyrazolate bridges. The exchange integrals (J) based on the Heisenberg model (H =—2JS1.S2) was estimated at—200.8 and—192.0 cm-1 for [Cu2(bampz)2Cl2] and [Cu2(bampz)2Br2], respectively.