Poly(imino imino ketone) (PIIK) was synthesized via palladium-catalyzed C-N cross coupling reaction of 1,4-bis-(4'-bromobenzoyl) benzene and p-phenylenediamine. In view of its good thermal stability and solubility, PIIK foams with low density between 80 mg/cm(3)-350 mg/cm(3) have been prepared via thermal induced phase separation and freeze-drying technology. The PIIK foam possessed high glass transition temperature (T-g = 193 degrees C) and good thermal stability with high decomposition temperature (T-d = 350 degrees C). Furthermore, these achieved foams also exhibited excellent mechanical properties, such as high modulus and compressive strength, as well as great elongation at break (ca. 20%). (C) 2013 Elsevier Ltd. All rights reserved.