By using a 2,2'-dimethyl-4,4'-bithiazole (dm4bt) ligand, Keggin polyanions, and different metal ions, nine Kegginbased compounds, namely, {[Ag(dm4bt)(2)][Ag-2(dm4bt)(3)]}(2)-(PW12O40)(112PWv2Wv11000) (1), [Cui(dm4bt)2][Cull(dm4bt)2-. (PW12O40)] (2), [Cu-I(dm4bt)(2)]4(SiW12040) (3), {[Zn(dm4bt)(2)](2)(SiW12O40)} (4), [Zn(dm4bt)(2)(H2O)](2)(HPMov2Movl0 (5), [Zn(dm4bt)(2)(Mo2O7)] (6), [Cd(dm4bt)3][Ci d:104).m4(2)bt(2)),(H2O)(PMo12040)12.2H20 (7), [Cd(dm4bt)3](PM012040)"(Hdm4bt) (8), and [Cd(dm4bt)(2)(H2O)212(HPMov2Movlio04o)" 2H20 (9), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, IR spectroscopy, and elemental analyses. Compounds 1-9 are zero-dimensional structures except compound 6, which exhibits a onedimensional structure. In compound 1, there are three isolated subunits: Keggin anions, binuclear [Ag2(dm4bt)3]2, and mononuclear [Ag(dm4bt)2]+ clusters. The binuclear [Ag-2(dm4bt)(3)](2+) cluster has a Ag-Ag bond. In compound 2, a monosupporting anion {[Cull(dm4bt)2](PW1204o))- and an isolated [Cu(dm4bt)(2)](+) cluster exist. By changing the transition metal ions, we obtained two different structures: a supramolecular 3 and a bisupporting anion in 4. By a one-pot method, we successfully obtained compounds 5 and 6, 7 and 8, respectively. In compound 5, the [Zn(dm4bt)(2)(H2O)](2+) subunit links adjacent PMo12 anions via SO interactions to form a one-dimensional (1D) supramolecular chain. In compound 6, some PMol, ions have transformed to [Mo207] 2n- chains. The [Zn(dm4bt)2](2+) clusters buckle up and down the chain. Compound 7 has a monosupporting anion and an isolated [Cd(dm4bt)3](2+) cluster. Compound 8 has isolated anions and [Cd(dm4bt)(3)](2+) clusters. By changing the pH of 7 and 8, a distinct supramolecular compound 9 was obtained. Additionally, the optical band gap, electrochemical, and photocatalytic properties of 1-9 have been investigated in detail. The carbon paste electrodes can be used as bifunctional amperometric and fluorescence sensors for recognition of Hg2+. The n-CPEs as electrochemical sensors can show accurate selectivity for NO2 ions in some common ions. In the fluorescence sensor experiment, fluorescence intensities decrease more than 80% when quenched by Hg2+.