A novel monomer, bis[4-(4-fluorobenzoyl)phenyl]phenylphosphine oxide, was synthesized through the reaction of bis(4-chloroformylphenyl) phenyl phosphine oxide with fluorobenzene. Three poly(ether ether ketone ketone)s derived from bis[4-(4-fluorobenzoyl) phenyl]phenylphosphine oxide and different aromatic bisphenols were prepared by aromatic nucleophilic substitution reactions. The resulting polymers had inherent viscosities in the range of 0.55-0.73 dL/g. The structures of the poly (ether ether ketone ketone)s were characterized with Fourier transform infrared and H-1-NMR. Thermal analysis indicated that the glass-transition temperatures of the poly (ether ether ketone ketone)s were higher than 200 degrees C, and the 5% weight loss temperatures in nitrogen were higher than 463 degrees C. All the polymers showed excellent solubility in polar solvents such as N-methyl-2-pyrrolidone, dimethylformamide, and dimethylacetamide and could also be dissolved in chlorinated methane. The polymers afforded transparent and flexible films by solvent casting. Organic phosphorous moieties also imparted good flame-retardancy to the polymers. (C) 2008 Wiley Periodicals, Inc.