In this paper the mixture of cyclohexanone and propylene glycol monomethyl ether acetate as the binary solvent assists supercritical dioxide to disperse and stabilize organic nano-particles in the presence of polyester/polyamine copolymer as a capping agent. High-resolution tunnel electron microscopy (HRTEM) and dynamic light scattering particle analyzer (DLS) were used to measure the particle sizes and stabilization of the dispersed organic pigments capped with polymeric surfactant in the mixed solvent after supercritical fluid processing. As shown in the results, the average sizes of 59 and 64 nm were obtained for diketopyrrolopyrrole (red 254) and copper phthalocyanine (green 36), respectively, which are stabilized in the binary solvent due to the dispersed organic nano-particles suspected by polymeric surfactant. UV-visible spectroscopy (UV-vis) and atomic force microscopy (AFM) were also used to verify this work. (C) 2013 Elsevier B.V. All rights reserved.