Complexes made by hosts that completely surround their guests provide a mean to stabilize reactive chemical intermediates, transfer biologically active cargo to a diseased cell, and construct molecular scale devices. By the virtue of inorganic host-guest self-assembly, the nucleation processes in the cavity of a {P8W48}-archetype phosphotungstate has afforded a nanoscale 16-GaIII-32-oxo cluster that contain the largest number of GaIII ions yet found in polyoxometalate chemistry. Catalytic activity via thus “Metal-Oxo Cluster within Cluster” Assembly has been preliminarily investigated. Besides, the hybrid aggregates composed of the inorganic {P8W48} and orgainc cyclic moiety has been studied.