We synthesized polyimide (PI) microparticles by a reaction between benzophenone-3,3,4,4-tetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether using polyvinylpyrrolidone as a dispersant in four different organic solvents, at different temperatures, with different amounts of the dispersing agent, and with different concentrations of monomers. After dispersion polymerization, PI microparticles in the size range 200-800 nm were obtained. Absorptions at 1,775 and 1720 cm(-1), due to the C=O group of PI, and at 1375 cm-1, caused by the stretching vibration of the C-N group due to a lactam ring, were observed in the IR spectrum, which suggested the successful synthesis of PI particles. Scanning electron microscopy analysis of microparticle morphology showed that the PI particle sizes increased with increasing temperature, concentration of dispersant, and concentration of monomers. In addition, the thermal stability is also discussed on the basis of the results of simultaneous Differential Scanning Calorimetry Modulated TA Instruments (DSC-TA) measurement. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 3671-3675, 2009