Two octamolybdate-based MOFs with unsaturated coordinated metal centers formulated as Cu(3)(Mo(8)O(26))(H(2)O)(2)(OH)(2)(L1)(4) (L1 = 4H-4-amino-1,2,4-triazole) (1) and Ag(4)(Mo(8)O(26))(L2)(2.5)(H(2)O) (L2 = 3,5-dimethyl-4-amino-4H-1,2,4-triazole) (2) were synthesized and structurally characterized by single-crystal X-ray diffractions. Complex 1 exhibits a 1D chain-like structure. In complex 2, 1D Ag-octamolybdate chains in the ac plane are covalently embedded into the 2D Ag-L2 layer, and the Ag-octamolybdate chains in the bc plane covalently link the 2D layers into 3D architecture. The two complexes both exhibit electrocatalytic activities toward generating H(2) from water with lowered overpotentials and enhanced currents, and the Cu complex exhibits better electrocatalytic activity toward generating H(2) from water than the Ag complex.