Thermal treatment of highly stable porous organic polymers based upon the Yamamoto polymerization of 2,2′,7,7′-tetrabromo-9,9′-spirobifluorene was done. The polymers are shown to be thermally and chemically stable. Upon thermal treatment the polymers are shown to have BET surface areas of ca. 2,000 m 2 /g and 2,500 m 2 /g respectively.