A Ni（Ⅱ） complex [Ni（bdpm）2（OAc）]2（N3）2.5H20 （bdpm = bis（3,5-dimethylpyrazol-1-yl）-methane） was synthesized and characterized by elemental analysis, 1R and single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group P21/c with a = 18.630（2）, b = 16.6624（19）, c = 19.821（2） A, fl = 90.146（2）°, V = 6152.9（12） A3, Z = 4, C48H80N22Ni2O9, Mr = 1226.76, Dc = 1.324 g/cm^3, F（000） = 2600 and μ = 0.680 mm^-1. The structure was refined to the final R = 0.0578 and wR = 0.1337 for 10848 independent reflections （Rint = 0.0311） and 6915 observed reflections （1 〉 2σ（I））. The complex contains two asymmetric molecules in the cell with small difference in bond distances and bond angles. Each Ni（Ⅱ） ion is bound by four nitrogen atoms of two chelating bdpm groups in a six-membered boat conformation and two oxygen atoms from one chelating bidentate acetate group to form a distorted octahedral geometry. The complex also contains azide anion outside acting as counteranion and two crystalline water molecules to link two discrete mononuclear cations though hydrogen bonds.
