This　study　highlights　the　innovative　use　of　increased　rare　earth　elements　to　enhance　the　dielectric　properties　of　materials　and　devices.　The　AlOC-129Ln　series,　features　the　highest　number　of　rare　earth　dopants　in　aluminum　oxo　clusters　to　date.　The　trivalent　ions　in　AlOC-129Ln　impart　a　high　dipole　moment,　significantly　elevating　the　dielectric　constant　(k)　of　the　doped　polymer　films.　AlOC-129Ce,　in　particular,　exhibits　the　largest　molecular　size,　which　enhances　interfacial　effects　and　achieves　a　relative　dielectric　constant　four　times　greater　than　that　of　undoped　polymers　and　1.5　times　higher　than　those　with　single　rare　earth　dopants.　The　substantial　molecular　size　(~2.5　nm)　and　robust　charge　scattering　and　trapping　capabilities　of　AlOC-129Ln　reduce　dielectric　loss　by　up　to　50%　at　high　frequencies.　Additionally,　its　excellent　solution　processability　enhances　breakdown　strength　by　147%,　ensuring　superior　electrical　stability.　This　research　demonstrates　the　versatility　of　the　cluster　doping　strategy　in　effectively　balancing　dielectric　constant　and　loss,　unveiling　the　promising　potential　of　solution-processable　cluster　materials　in　electronic　devices.　©　2025　SIOC,　CAS,　Shanghai,　&　WILEY-VCH　GmbH.