Lanthanide-organic complexes based on polyoxometalates: Solvent effect on the luminescence properties

► The solvent effect on the luminescence property of POMs-based lanthanide-organic complexes. ► ESI-MS analyses illuminate the correlation between the structure and luminescence property. ► The dimeric cations have eight active sites of solvent coordination. ► The aggregated state structure of dimer cation remains unchanged in solution. ► Luminescence associating with ESI-MS is a new method for investigating the interaction of complex and solvent.