Functionalized nanoparticles, which are obtainable by combining in a first step a functionalized dyestuff, a silicon-based spacer and a catalyst, and in a second step reacting the product obtained in the first step with a co-reactive organic silicon, aluminum, zirconium or titanium compound. Optionally, the thus obtained functionalized nanoparticles can be combined or encapsulated with a polymer. The functionalized nanoparticles are useful as colorants and fluorescents in plastics, paints, inks, electronic materials, cosmetic articles, and the like.