Highly porous organic nanoparticles have been prepared by adapting a novel method, sol-emulsion-gel. process, through stable dispersion of nanometer-scaled emulsion droplets into continuous phase of supercritical carbon dioxide (ScCO2), sol-gel chemistry in emulsion droplets, and then supercritical drying. This principle offers faithful preparation of nanoparticles (35-90 nm in diameter) having pores of 1-3 nm in radius and high specific surface area (over 2000 m(2)/g).