Octa(aminophenyl)silsesquioxane (CAPS) was prepared from octa(nitrophenyl)silsesquioxane (ONPS) by using the stable, inexpensive, and readily available hydrazine hydrate as the reducing agent with a yield of around 86%. The product was characterized by FTIR, GPC, H-1 NMR, Si-29 NMR, and XRD. It was found that the time period for preparation of ONPS from octaphenylsilsesquioxane could be considerably shortened, reaching the complete nitration and avoiding double nitration of the aromatic rings. The polyimides were prepared by the reaction of N,N'-bismaleimido4,4'-diphenylmethane with OAPS and 4,4'-diamino-diphenyl ether. The structure of resulting organic-inorganic hybrid nanocomposites was characterized by XRD and FTIR. The decomposition temperature and char yield of resulting materials increased with increasing CAPS loading. The DSC data showed that the glass transition temperature of nanocomposite was enhanced by 36 degrees C with the content of OAPS around 15 wt %. As the feed amount of OAPS increased further, the decrease in T-g's could be observed. (c) 2006 Wiley Periodicals, Inc.