This paper reports a facile approach to functionalize silica nanoparticle (SNP) surfaces, using 4-isocyanato-4'-(3,3'-dimethyl-2,4-dioxo-azetidino)diphenyl methane (MIA) as a reaction agent. Incorporation of MIA onto SNP surfaces is demonstrated with infrared spectrometry, H-1 NMR, and thermal analysis. The amounts of MIA moieties bonded to SNP surfaces are adjustable with the MIA contents in reaction systems. This modification approach brings azetidine-2,4-dione groups, which are selectively reactive toward primary amines, to SNP surfaces and the result is that the MIA-modified SNPs are effective and divergent intermediates for preparation of SNP-based nanohybrid materials. Consequently, SNP-cored polystyrene star polymers and SNP-polyhedral oligomeric silsesquioxane (POSS) nanohybrids are prepared with reaction of MIA-modified SNPs with amine-functionalized agents, demonstrating the applications of MIA-modified SNP particles in nanomaterial preparations. (C) 2009 Elsevier Inc. All rights reserved.