Silicon-containing organic/inorganic composites were prepared from poly(styrene-co-allyl alcohol) (PSAA) and soluble starch (SS) by infusing SiCl 4 into them using supercritical carbon dioxide (SC CO 2 ) as the carrier medium. The resulting hybrid materials were studied by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA) and elemental analysis. The results of these studies indicated that 12Β±15% silicon, in the form of SiO 2 , was homogeneously dispersed throughout the PSAA and SS matrices. As a consequence of the interpenetrated SiO 2 network, the thermal and solubility properties of the composites were altered relative to the virgin materials. SC CO 2 was also employed as the reaction medium in platinum-catalyzed hydrosilation reactions. The diallyl ether of 1,3-bis(hexafluoro-2hydroxy-2-propyl)benzene (1,3-HFAB) was used in a model reaction along with dimethylphenylsilane as the sililating agent. The reaction mixtures from hydrosilation reactions conducted in both benzene and in SC CO 2 were analyzed by 1 H-NMR spectroscopy. Comparison of the spectra indicated that the SC CO 2 reaction provided higher percent conversion in shorter amounts of time. When the 1,3-HFAB diallyl ether was reacted with disilanes and siloxanes, silicon-and fluorine-containing oligomers were obtained in good yields.