The reaction between polyoxometalate (POM) [TBA]₁₂[WZn{Zn(H₂O)}₂(ZnW₉O₃₄)₂] (TBA = tetrabutyl ammonium) and lanthanide (Ln) nitrate (Ln = La, Eu and Tb) in a mixed solvent of CH₃CN and DMF yielded three noncentrosymmetric diamondoid Ln–POM solid materials, {[Ln₂(DMF)₈(H₂O)₆][ZnW₁₂O₄₀]}·4DMF (Ln–POM; Ln = La, Eu and Tb). In these compounds, the {ZnW₁₂O₄₀} unit, transferred from the metastable [WZn{Zn(H₂O)}₂(ZnW₉O₃₄)₂] cluster, acts as a tetradentate ligand to connect with four Ln nodes, while the Ln ion links up two {ZnW₁₂O₄₀} units. These compounds generated interesting luminescence emissions that are dependent on the Ln ions and their ratios. White light emission was obtained by a doped approach with a rational ratio of the Eu³⁺ and Tb³⁺ ions.