Dodecanuclear hexagonal-prismatic M12L18 cages were prepared by a subcomponent self-assembly process with commercially available pyridinecarboxaldehyde, m-xylenediamine, and cadmium(II) perchlorate or manganese(II) perchlorate. The NMR spectrum of the Cd cage shows that there are three independent ligand sets, and the X-ray crystal structure of the Mn cage reveals that the structure has both fac-Delta- and mer-Lambda-configured metal centers in a 1:1 ratio. The cage structure also has a large cavity that contains five perchlorate anions.