Although　the　synthesis　of　giant　lanthanide　(Ln)-containing　polyoxotungstates　(POTs)　has　long　been　actively　pursued,　it　remains　challenging　to　encapsulate　high-nuclearity　Ln-O　clusters　in　POT　shells　because　of　the　highly　complicated　assembly　process.　This　work　demonstrates　a　simple　synthetic　strategy　of　using　lacunary　POT　precursors　to　assemble　with　in　situ　generated　Ln-O　clusters　in　the　presence　of　basic　N-containing　ligands,　which　exert　a　slow-releasing　effect　for　Ln3+ions　in　alkaline　conditions.　With　this　strategy,　two　giant　Ln30-cluster-embedded　polyoxometalates　(POMs)　H38Na10K14(TMEDA)8[Ln30Ge12-W107O420(OH)2(H2O)14]·solvents　(1Ln)　(Ln　=　Sm,　Eu)　have　been　successfully　synthesized,　which　not　only　represent　two　rare　high-nuclearity　POM　macromolecules　with　over　100　W　atoms　but　also　a　unique　Ge2W7⊂　Ln30⊂　W100multishell　configuration.　The　incorporated　Ln-O　clusters　in　[Ln30Ge12W107O420(OH)2(H2O)14]62-(Ln30W107)　with　a　nuclearity　of　30　are　larger　than　any　known　Ln-clusters　observed　in　POM　chemistry.　Additionally,　they　contain　the　largest　number　of　Sm　and　Eu　centers　for　any　POMs　reported　to　date.　Interestingly,　the　unique　structural　features　and　the　high-nuclearity　Ln-O　clusters　endow　Ln30W107with　excellent　proton　conductivities　over　a　wide　temperature　range　and　unusual　luminescence　properties.　©　Journal　of　Gastrointestinal　Oncology.　All　rights　reserved.