A new monomer containing sulfone and imide linkages, bis{4-[4-(p-phenoxyphenylsulfonylphenoxy)benzoyl]-1,2-benzenedioyl}-N,N,N',N'-4,4'-diaminodiphenyl ether (BPSPBDADPE), was prepared by the Friedel-Crafts reaction of bis(4-chloroformyl-1,2-benzenedioyl)-N,N,N',N'-4,4'-diaminodiphenyl ether with 4,4'-diphenoxydiphenyl sulfone. Novel copolymers of poly(ether ketone ketone) and poly(ether ketone sulfone imide) were synthesized by electrophilic Friedel-Crafts solution copolycondensation of terephthaloyl chloride with a mixture of DPE and BPSPBDADPE. The polymers were characterized by different physico-chemical techniques. The polymers with 10-25 mol% BPSPBDADPE are semicrystalline and had increased T (g)s over commercially available PEEK and PEKK (70/30) due to the incorporation of sulfone and imide linkages in the main chains. The polymer IV with 25 mol% BPSPBDADPE had not only high T (g) of 194 A degrees C but also moderate T (m) of 338 A degrees C, having good potential for melt processing and exhibited high thermal stability and good resistance to common organic solvents.