The use of a hyperbranched polymer as a building block for the synthesis of a microporous organic polymer was demonstrated. Hyperbranched polyphenylenes (HBPs) were prepared from (3,5-dibromophenyl)boronic acid, which contained numerous unreacted bromophenyl end groups. Utilizing metal-catalyzed coupling reactions between these functional groups, cross-linked porous polymers were obtained. Although the HBPs did not show porosity, their cross-linked polymers had highly porous structures with Brunauer-Emmett-Teller surface areas of up to 2030 m(2)/g. An insoluble porous thin film was fabricated by spin casting of a solution containing a HBP followed by Sonogashira cross-coupling reaction. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2336-2342