Bridged polysilsesquioxanes containing urea groups (ureasils) exhibit a broad photoluminescent emission in the visible spectrum. For a particular bridged polysilsesquioxane synthesized by the hydrolytic condensation of a precursor prepared by reaction of 4,4'-[1,3 phenylenebis-(1-methylethylidene)]bis(aniline) (BSA) with 3-(isocyanatepropyl)triethoxysilane (IPTES), we show that the broad photoluminescent band could be transformed into a relatively narrow emission band located in the red region of the spectra, by doping with Safranine-O. The spectral overlap between the host emission and the dye absorption generated an efficient energy transfer process (antenna effect). Absorption, emission, and triplet-triplet absorption spectra revealed an efficient dispersion of the dye in the ureasil as well as the presence of strong host-guest specific interactions. (C) 2007 Wiley Periodicals, Inc.