Two new Keggin-type polyoxoanion-templated inorganic-organic hybrids, [Cu(3,4-bpo)2(H2O)(SiW12O40)] ⋅ (3,4-H2bpo) ⋅ 7H2O (1), and [Cu(4,4′-Hbpo)2(4,4′-bpo)(H2O)(SiW12O40)] ⋅ 3H2O (2) (3,4-bpo = 2-(3-pyridyl)-5-(4-pyridyl)- 1,3,4-oxadiazole, 4,4′-bpo = 2,5-bis(4-pyridyl)-1,3,4-oxadiazole), have been hydrothermally synthesized by changing the terminal N-donor’s orientation of the nonlinear ligands. X-ray structural analyses indicate that compound 1 shows a two-dimensional (2D) (4,4) grid sheet. The discrete SiW12O404− anions as templates locate on the square voids of the sheet. Compound 2 exhibits an arm-shaped chain structure. It is believed that the isomeric organic ligands play a key role in the structure control of the self-assembly processes. Furthermore, compound 1 bulk-modified carbon paste electrode (1-CPE) displays good electrocatalytic activity toward the reduction of nitrite.