A novel monomer of tetrachloroterephthaloyl chloride (TCTPC) was prepared by the chlorination of terephthaloyl chloride catalyzed by ferric chloride at 175-180 degrees C for 10 h and confirmed by FTIR, MS, and elemental analysis. Five new polychloro substituted poly (aryl ether ketone sulfone)s (PEKSs) with inherent viscosities of 0.68-0.75 dL/g have been prepared from 4,4'-diphenoxydiphenylsulfone, 4,4-bis(2-methylphenoxy) diphenylsulfone, 4,4-bis(3-methylphenoxy)diphenylsulfone, 4,4'-bis(2,6-dimethylphenoxy)diphenylsulfone, and 4,4'-bis(l-naphthoxy)-diphenylsulfone with TCTPC by electrophilic Friedel-Crafts acylation in the presence of DMF with anhydrous AlCl3 as a catalyst in 1,2-dichloroethane, respectively. These polymers having weight-average molecular weight in the range of 76,600-83,900 are all amorphous and show high glass transition temperatures ranging from 213 to 250 degrees C, the 5% weight loss temperature over 450 degrees C, high char yields of 60-67% at 700 degrees C in nitrogen and good solubility in CHCl3 and polar solvents such as DMF, DMSO, and NMP at room temperature. All the polymers formed transparent, strong, and flexible films, with tensile strengths of 85.1-90.8 MPa, Young's moduli of 2.52-3.24 GPa, and elongations at break of 21.227.2%. (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 108: 1049-1054, 2008.