Three POMs–based inorganic–organic frameworks, namely, [Cu2(L)2(SiW12O40)(H2O)2]·6H2O (1), [Co2(L)2(SiW12O40)(H2O)8]·8H2O (2) and [Ni2(L)2(SiW12O40)(H2O)8]·6H2O (3), (L=1,1′-(1,4-phenylene-bis(methylene))-bis(pyridine-3-carboxylic acid)), have been synthesized and characterized by elemental analyses, IR, XRPD, TG, and single crystal X-ray diffraction. Compound 1 contains 1D double chains decorated by {Cu2(L)4(H2O)2} units and the 1D chains and POMs are stacked to yield 2D frameworks. Compound 2 displays a 2D network constructed from 1D zigzag chains and POMs arranged in ABAB mode. Compound 3 consists of big square girds and the POMs are dispersed in the middle of the two adjacent girds, forming 2D networks. Compounds 1–3 all show structural integrity in aqueous solutions at different pH values and in common organic solvents. Additionally, the fluorescence and electrochemical properties of compounds 1–3 are also investigated. Compounds 1–3 exhibit good electrocatalytic activities for the reduction of NaNO2 and H2O2.