Through tuning the N-donor site of the pyridyl group in 5-(x-pyridyl)-1H-tetrazole ligands (x = 2, 4), four new Keggin-based compounds, [Cu₇(2-ptz)₈(OH)₂(H₂O)₂(HPMo^VI₁₀Mo^V₂O₄₀)]·4H₂O (1), [Cu₅(2-ptz)₆(HPMo^VI₁₀Mo^V₂O₄₀)(H₂O)₄]·4H₂O (2), [Ag₆(4-ptz)₄(H₂SiMo₁₂O₄₀)] (3) and [Ag₅(4-ptz)₄(H₂PMo₁₂O₄₀)]·5H₂O (4) (2-ptzH = 5-(2-pyridyl)-1H-tetrazole, 4-ptzH = 5-(4-pyridyl)-1H-tetrazole), were successfully synthesized under hydrothermal conditions and structurally characterized. Compound 1 possesses two kinds of Cu^II subunits: penta-nuclear clusters and mono-nuclear subunits, which connect with each other to form a one dimensional (1D) stair-like metal–organic chain. The adjacent 1D stair-like chains are further linked by tetradentate Keggin anions to construct a 2D layer. In compound 2, the tetra-nuclear Cu^II clusters and mono-nuclear Cu^II subunits construct a 2D metal–organic layer, which is further linked by bidentate Keggin anions to build a 3D framework. In compound 3, the 4-ptz ligand links Ag^I ions with tetrazole groups to form 1D infinite Ag–ptz chains, which are extended by the pyridyl group of 4-ptz and the tetrazole groups of other 4-ptz molecules to construct a 2D layer. The adjacent 2D layers are further linked by 6-connected Keggin anions to build a 3D framework. In compound 4, the 4-ptz ligands are linked by Ag^I ions to form 1D infinite Ag–ptz belts. The Keggin anions are linked by Ag^I ions to construct another infinite inorganic chain, in which each Keggin anion provides six oxygen atoms to coordinate with the Ag^I ions from adjacent Ag–ptz belts to construct a 2D layer. The roles of the ptz ligands with different N-donor sites in the construction of multinuclear clusters and 1D chains are discussed. The electrochemical and photocatalytic properties of the title compounds were investigated as well.