This work aims at the design of photoactive inorganic filler by covalently attaching tri(methoxy)silyl-functionalized bis(acyl)phosphane oxides (TEMSI2-BAPO) onto silica particles. The immobilization of the photoactive groups is evidenced by spectroscopic measurements and thermal gravimetric analysis. The modified particles are then incorporated into thiol-ene resins to study the efficiency of the Norrish type I photofragmentation reaction of the covalently bound TEMSI2-BAPO derivatives. The photopolymerization kinetics of the thiol-ene system is monitored by FT-IR spectroscopy and photo-DSC upon prolonged exposure with UV-light and compared with the results achieved with IRGACURE 819 (free BAPO). Rapid curing and high conversion yields are obtained evidencing the high efficiency of the photoactive particles. In addition, negative-toned patterns are inscribed in thin thiol-ene films by photolithographic processes and characterized by microscopic techniques demonstrating the versatile applicability of the photoactive particles. (c) 2016 Wiley Periodicals, Inc.