Lacunary polyoxometalates (POMs), featuring highly reactive vacant sites, serve as valuable building blocks and precursors for the rational design of functional materials with widespread applications in catalysis, analytical chemistry, energy conversion and storage, medicine, and optical materials. While diverse Keggin-type polyoxotungstates, including both plenary and lacunary species, have been synthesized through dehydration condensation reactions and equilibrium displacement in aqueous solvents, the isolation and use of lacunary polyoxomolybdates remain challenging. To address this, the current study proposes a "ligand-directed top-down synthetic approach" for producing lacunary polyoxomolybdates from plenary Keggin-type species in organic solvents. By reacting plenary Keggin-type polyoxomolybdates [α-XMo