Highly dispersive and functionalized mesoporous silica nanoparticles (MSNs) 50-100 nm in diameter were formed by versatile surface modification through photopolymerization of organic molecules having vinyl groups. Hydrophilic polymers, hydrophobic chains, poly(N-isopropylacrylamide), and poly(N-vinylcarbazole) were easily attached to methacryl groups as a reactive site on the particle surface. We obtained MSNs having high dispersibility in various media and functionality, such as thermosensitivity and photoluminescence, using the facile technique.