Two organic-inorganic hybrid bimolybdenum-capped tetra-Ni-II sandwich-type molybdogermanates, namely, (H2L)(4)[Ni-4(H2O)(2){B-alpha-GeMo9O34 (MoO2)}(2)]center dot 6H(2)O (1), [Ni-2(HL)(4)(H2O)(2)][Ni-4(H2O)(2){B-alpha-GeMo9O34(MoO2)}(2)]center dot 12H(2)O (2), L = 2,4,5-tri(4-pyridyl)imidazole, were prepared with hydrothermal synthesis method and characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, thermogravimetric analysis, and single-crystal X-ray diffraction. Their magnetic properties and electrochemical properties were investigated. The results show that compounds 1 and 2 contain a new bimolybdenum-capped sandwich-type heteropolymolybdate anion, [Ni-4(H2O)(2){B-alpha-GeMo9O34(MoO2)}(2)](8-). The compound 1 is a zero-dimensional supramolecular compound, and the supramolecular architecture of compound 2 is constructed from covalent layers through hydrogen bonds and pi-pi interaction. The two compounds both present electrocatalytic activities for the reduction of nitrite.