Nanoporous silica-quantum dot composites are produced using an amphiphilic organotrialkoxysilane containing a thermally reversible urethane moiety. Nanoporous silica is formed by co-condensation of the amphiphile and a silicate precursor (see Figure). After heating, the urethane dissociates to form an isocyanate group tethered to the silica. This can be used to make thiol-functionalized nanoporous silica that can encapsulate cadmium selenide nanoparticles.