Novel high-nuclearity lanthanide clusters (Ln(17)) are generated in situ in the coordination-driven self-assembly. A metal-cluster-directed symmetry strategy for building metal coordination cages is successfully applied to a lanthanide system for the first time. A new family of octagonal-prismatic lanthanide coordination cages UJN-Ln, formulated as [Ln(mu(3)-OH)(8)] [Ln(16)(mu(4)-O) (mu(4)-OH) (mu(3)-OH)(8)(H2O)(8)(mu(4)-dcd)(8)] [ (mu(3)-dcd)(8)]center dot 22H(2)O (Ln = Gd, Tb, Dy, Ho, and Er; dcd = 3,3-dimethylcyclopropane-1,2-dicarboxylate dianion), have been assembled from the unique Ln(17) clusters and simple cliplike ligand H(2)dcd. Apart from featuring aesthetically charming structures, all of the compounds present predominantly antiferromagnetic coupling between the corresponding lanthanide ions. Additionally, the intense-green photoluminescence for UJN-Tb and magnetic relaxation behavior for UJN-Dy have been observed. Remarkably, UJN-Gd shows a large magneto caloric effect (MCE) with an impressive entropy change value of 42.3 J kg(-1) K-1 for Delta H = 7.0 T at 2.0 K due to the high-nuclearity cluster and the lightweight ligand. The studies highlight the structural diversity of multigonal-prismatic metal coordination cages and provide a new direction in the design of cagelike multifunctional materials by the introduction of lanthanide clusters and other suitable cliplike ligands.