A new molecular nickel catalyst, [Bz-1-MeIm]2 [Ni(tdas)2]( [Bz = benzyl, 1-MeIm = 1-methyl-limidazolium, tdas2− = 1,2,5-thiadiazole-3,4-dithiolate) was synthesized and characterized by elemental analysis, single crystal X-ray diffraction, infrared spectrum, ultraviolet-visible spectrum and thermo-gravimetric analysis. The as-prepared nickel complex crystallizes in the triclinic system with space group P−1 in which weak interactions such as S···N, N···N, π···π, N···S, and C−H···π further induce the formation of a three-dimensional network structure. Electrochemical studies indicated that the complex can electro catalyze the hydrogen evolution of buffered aqueous solution (pH 7.0) and DMF solution. Under an overpotential (OP) of 837.6 mV, the turnover frequency (TOF) reached 772.85 mols of hydrogen per mol of catalyst per hour from the water buffers solution with the turnover numbers (TONs) of 1545.7 after 2 h of reaction.