Cardo poly(arylene ether sulfone)s are an important type of high performance engineering thermoplastics. They possess unique properties, including good processability, thermal stability, and good insulating and mechanical properties as well as excellent chemical resistance. They are potential candidates for the preparation of ion exchange, water purification, and gas separation membranes. This review focuses on the synthesis of phenolphthalein-based cardo poly(arylene ether sulfone) s, including synthesis of cardo bisphenols and their polymers, and their application to separation membranes. (C) 2012Wiley Periodicals, Inc. J. Appl. Polym. Sci. 128: 1-12, 2013