Phenylphosphine oxide-containing poly(arylene ether)s were prepared by the aromatic nucleophilic displacement reaction of a new phenylphosphine oxide-containing bisphenol with activated aromatic difluorides in the presence of anhydrous potassium carbonate in N,N’-dimethylacetamide at 155-degrees-C or in sulfolane at 200-degrees-C. The phenylphosphine oxide-containing bisphenol was prepared in two steps from bis(4-fluorophenyl)phenylphosphine oxide and 4-methoxyphenol. The polymers exhibited inherent viscosities of 0.57-0.75 dl g-1 and glass transition temperatures of 177-213-degrees-C. Thermogravimetric analyses showed 5% weight loss in the ranges of 447-471-degrees-C in air and 480-512-degrees-C in nitrogen. Unoriented thin films exhibited tensile strengths, moduli and break elongations at 23-degrees-C of 8.1-11.1 ksi, 275-370 ksi and 42-109%, respectively. Limiting oxygen indices of 0.30-0.33 were calculated based on polymer char residues at 850-degrees-C in nitrogen. Phenylphosphine oxide-containing poly(arylene ether)s exhibited excellent resistance to an oxygen plasma environment with weight loss rates of one to two orders of magnitude lower than that of Kapton(R) HN. The chemistry, and physical and mechanical properties of these polymers, as well as their oxygen plasma resistance, are discussed.