Microporous polymer films are attractive materials with potential application in the fields of electronics, photonics, and biotechnology. Chemical and thermal stabilities of the microporous polymer films are required for their materials application. Besides preparation by conventional photolithography, we have reported that honeycomb-patterned porous polymer films are prepared by a method utilizing the condensation of small water droplets on solutions of amphiphilic copolymers. Here, we show preparation of honeycomb-patterned microporous films of a thermally and chemically stable material, polyimide. A water-template-assisted honeycomb structure was formed from a polyion complex of polyamic acids and dialkylammonium salt. The pore size of films was controlled by the casting volume of polymer solution. The patterned polyion complex film converted into polyimide by simple chemical treatment, keeping the porous structure. Self-supporting microporous polyimide films are fabricated. The honeycomb-structured film has high thermal and chemical stability like that of conventional cast films of polyimides.