Polyoxometalates (POMs) have received increasing attention over the last decades for extending their application and properties that originate from novel structures. For the synthesis of a variety of POM structures, multivacant lacunary POMs are key precursors, which are typically synthesized by empirically controlling the complex equilibrium in aqueous solvents. Unfortunately, despite the excellent catalytic and electrochemical properties of "polyoxomolybdates", only one multivacant lacunary species, i.e., [A-a-PMo 9 O 34 ] 9À , has been identified and isolated because multivacant lacunary polyoxomolybdates are typically unstable. Here we report a liganddirected approach for the selective formation of an unprecedented lacunary polyoxomolybdate in organic solvents. By structure transformation of a pyridine-coordinated [A-a-PMo 9 O 34 ] 9À , a new g-Keggin-type divacant lacunary polyoxomolybdate [g-PMo 10 O 36 ] 7À was obtained, which can be further used as a precursor for synthesizing a POM-organic hybrid.