ABSTRACTSynthesis of hybrid aerogel materials that contain both selectively reactive nanoparticles and nanoparticles with appreciable magnetic susceptibilities will be reported. This has been achieved by a two stages process. First silica-bioderived polymer hybrid aerogels with incorporated metal ions were synthesized and then reduced by photolytically induced chemical reductions or decompositions. For example, silica-chitosan hybrid gels were prepared, Au(III) ions were coordinated to the chitosan, and, after forming the Au(III)-silica-chitosan aerogel by SCL extraction, UV photolysis afforded gold nanoparticles of controlled size in the aerogel. Second, an iron-containing organometallic compound, such as iron carbonyl itself, was absorbed into the aerogel, and then heating or photolysis afforded reduced metal decomposition products. Ferromagnetic organic/inorganic hybrid products containing Au(0) nanoparticles were obtained. Their size (TEM), crystallographic, optical and magnetic properties are discussed. Reactions of thiol compound with the metal nanoparticles in the aerogels were studied.