This article describes the preparation and characterization of fluorescent and magnetic composite particles of poly(styrene-co-methacrylic acid-co-2-naphthyl methacrylate) (poly(St/MAA/NMA)). First, monodisperse (D-w/D-n < 1.1) and fluorescent poly(St/MAA/NMA) submicron particles were prepared using emulsifier-free emulsion polymerization by varying the concentration of the fluorescent comonomer, i.e., NMA. Composition of the particles was characterized by H-1 NMR, FT-IR, GPC, and DSC analyses. The molecular weights and particle size of the particles were dependent on the NMA concentration. Second, Fe3O4 nanoparticles were immobilized onto the poly(St/MAA/NMA) submicron particles to give rise to multifunctional properties. The morphology and particles size were characterized by FE-SEM and CHDF. These poly(St/MAA/NMA)/Fe3O4 composite particles exhibited both fluorescent properties under UV irradiation at 365 nm and magnetic properties. Photo-luminescent (PL) intensity of the particles showed linear dependence with NMA concentration. (C) 2009 Elsevier Inc. All rights reserved.