Occlusion of uranyl ions (UO 2 2 + ) in the pore channels of mesoporous MCM-41 and MCM-48 molecular sieves was accomplished using direct template ion-exchange method, and the samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance ultraviolet-visible spectroscopy (DRUV-VIS), and fluorescence spectroscopy. A shift in U O stretching IR band (Δν=-34cm - 1 ), and the appearance of broad and diffused bands in the fluorescence spectra (480-620nm) of the UO 2 2 + -exchanged samples indicate a definite electronic interaction of UO 2 2 + species with the silicate (≡Si O - ) surface. This inference is corroborated by DRUV-VIS results. Calcination in air/N 2 at 823K resulted in the formation of well-dispersed α-U 3 O 8 /α-U 3 O 7 moieties, accompanied by a marginal decrease in the concentration of UO 2 2 + groups. The binding of UO 2 2 + species to mesoporous materials framework remained intact even after calcination. The molecular sieves loaded with uranium oxide species showed appreciable activity, both for the oxidation of CO and for adsorption/decomposition of CH 3 OH.