The inorganic-organic hybrid compound composed of the novel infinite-chain Pd(II) complex and the polyoxometalate ({[(en)Pd(p-bpy)](2)[alpha-SiW12O40]center dot 8DMSO center dot 4DMF}(infinity) (1a:1 with 8DMSO center dot 4DMF; monoclinic P2(1)/c(No. 14), a = 15.0188(3) angstrom, b = 15.6962(3) angstrom, c = 26.9793(6) angstrom, beta = 106.3580(10)degrees, V = 6102.6(2)angstrom(3)) has been successfully synthesized by the reaction of [(en)Pd(OH2)(2)](2)[R-SiW12O40](2) with 4,4'-bipyridine (p-bpy). The treatment in dry N-2 at 50 degrees C or evacuation at room temperature forms {[(en)Pd(p-bpy)](2)[alpha-SiW12O40]center dot 6.0DMSO}(infinity) (1b:1 with 6DMSO) with a drastic reduction of the interlayer spacing, which is characterized by the powder diffraction analysis and the single-crystal analysis of 1c (1 with 4.5DMSO center dot 3.5DMF; monoclinic P2(1)/a (No. 14), a = 14.200(9) angstrom, b = 22.8865(8) angstrom, c = 14.8558(5) angstrom, beta = 114.7990(10)degrees, V = 4383.0(2) angstrom(3)). Compound 1b reversibly sorbs the hydrophilic molecules with the maintenance of the intrinsic structure, which is much different from hydrophobic guest-inclusion properties reported in the other Pd-based supramolecular systems.