Eight members of basketlike mixed-valent compounds, formulated as (H3O}(2){Fe-III(2,2'-bpy)(3)}(6){Sr subset of(P6Mo4Mo14O73)-Mo-V-O-VI}(2)center dot 9H(2)O (1), {H-2(4,4'-bpy)}(5){[Ni(4,4'-bpy)(H2O)(3)](2)[Ni(H2O)(2)][Sr subset of(P6Mo2Mo16O73)-Mo-V-O-VI](2)}center dot 12H(2)O (2), (Cu-2(bim)(4)(H2O)}(2){[Cu(bim)(2)](2)[Cu(bim)(H2O)](2)Cu(H2O)(2)[Sr subset of(P6Mo3Mo15O73)-Mo-V-O-VI](2)}center dot 16H(2)O (3), {H3O}(4){[Cd(phen)(2)](2)Sr(H2O)(5)[Sr subset of(P6Mo4Mo14O73)-Mo-V-O-VI]}center dot H2O (4), {Cu(bim)(2)} ([Cu(bim)(2)](2){Cu(Hbim)(H2O)(2)][Ca subset of(P6Mo3Mo15O73)-Mo-V-O-VI]}center dot 9H(2)O (5), {[Cu(2,2'-bpy)(H2O)](4)[Ca subset of(P6Mo2Mo16O73)-Mo-V-O-VI}center dot 4H(2)O (6), {[Cu(2,2'-bpy)(H2O)](4)[Sr subset of(P6Mo2Mo16O73)-Mo-V-O-VI]}center dot 8H(2)O (7), and {[Cu(2,2'-bpy)(H2O)](4)[Ba subset of(P6Mo2Mo16O73)-Mo-V-O-VI]}center dot 8H(2)O (8), have been hydrothermally synthesized and structurally characterized via elemental analysis, thermogravimetry (TG), infrared (IR) spectroscopy, ultraviolet-visible light (UV-vis) spectroscopy, X-ray photoelectron spectroscopy (XPS), and single-crystal X-ray diffraction (XRD). The structural analysis shows that all the compounds contain basket-shaped polyoxoanions [M subset of(P6MonMo18-nO73)-Mo-V-O-VI]((6+n)-) (M = Ca, Sr, Bo; n = 2, 3, or 4) (abbreviated as {P6Mo18O73}) as building units, which consists of a tetravacant gamma-Dawson-type{P2Mo14} unit and a "handle"-shaped {P4Mo4} segment encapsulating a single alkaline-earth metals cation M2+ in the central cavity. Compound 1 presents a zero-supported basketlike structure decorated by three discrete {Fe(2,2'-bipy)(3)} fragments. Compound 2 is monosupported by {Ni(4,4'-bipy)(H2O)(3)} subunit. Compound 3 and 4 are bisupported by copper complexes and cadmium complexes, respectively. Compound 5 exhibit a trisupported basket cluster modified with two {Cu(bim)(2)}(2+) and one (Cu(Hbim)(H2O)}(3+) cations. Compounds 6-8 are isostructural clusters exhibiting similar tetra-supported structures. Compound 1, 2, and 4 represent the first basket-like hybrids containing transition-metal iron, nickel, and cadmium, respectively. In addition, compounds 2, 6, 7, and 8 are observed for the first time as a two-electron-reduced basket form. The compounds display good electrocatalytic activity upon the reduction of nitrite, and fluorescent properties.