In the fabrication of polyimide (PI) spherical nanoparticles by the reprecipitation method, intriguing uniquely shaped objects, including doughnut-like and/or hollow, and polymeric soccer ball-shaped PI nanoparticles are rarely obtained. Furthermore, P1 fine particles, which possess a hollow core and some 100 nm-sized surface pores leading to the inner hollow, were reproducibly obtained by the improved reprecipitation method.