Fabrication of nanoparticle colloids of organic semiconductors is a fascinating subject not only because of its unique properties from the size-effects but also because of its practical advantage of low manufacturing cost for various electronic devices. The detail of its dispersion stability, however, is not studied properly, especially for organic colloids fabricated by pulsed laser ablation in liquid (PLAL) technique. In this study, the primary factor of stabilizing nanoparticles of N,N'-ditridecyl-3,4,9,10-perylenetetra¬carboxylic diimide (PTCDI-C13) during PLAL is determined by observing the dispersion stability of its colloids prepared in various organic solvents. It is clearly proved that the functional group of solvents is the decisive factor for the dispersion stability of PTCDI-C13 colloids. This result can be applied to other organic semiconductors and promote the advent of a new methodology of organic electronics utilizing highly stable nanoparticle colloids of organic semiconductors for low-cost fabrication of electronic devices.