By using an uncommon bi(triazole) ligand and tuning the substituent group on the ligand in the Ag–polyoxometalate (POM) reaction system, three new three-dimensional (3D) Keggin-based metal–organic complexes (MOCs), [Ag₄(L¹)₂(PW^VI₁₁V^VO₄₀)]·∼14H₂O (1), Ag₄(L¹)₂(HSiW^VI₁₁V^VO₄₀)]·∼25H₂O (2) and [Ag₄(L²)₂(H₂O)₂(PW^VI₁₁V^VO₄₀)]·2H₂O (3) (L¹ = 4-(1H-1,2,4-triazol-3-yl)-2H-1,2,4-triazolyl and L² = 3-(pyrid-2-yl)-5-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolyl), have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, IR spectra and elemental analyses. In compounds 1–3, the Keggin-type POMs act as highly connected inorganic ligands and are modified by the Ag–triazole polymeric motifs. Compounds 1 and 2 exhibit similar (4,4,4,5,10)-connected 3D frameworks with {4¹⁴·6¹⁶·8¹⁵}{4⁴·6²}³{4⁶}{4⁹·6}² topologies, which are constructed from infinite one-dimensional (1D) [Ag₄(L¹)₂]_n chains and 10-connected polyoxoanions. Compounds 1 and 2 represent the first examples of coordination complexes using bi(triazole) as a ligand. In compound 3, there is a twisted 1D chain consisting of [Ag₄(L²)₂]⁴⁺ subunits, which are linked by 6-connected Keggin anions to generate a complicated 3D framework with a {4·6·8}{4²·6²·8²}{4²·6}{4³·6²·8}{4³·6³}{4³·6⁴·8⁵·10³}{4⁴·6²} topology. The substituent group on the bi(triazole) plays a key role in the assembly and structures of the title compounds. The photocatalytic activities and selectivities, and the electrochemical properties of compounds 2 and 3 have been investigated.