Novel cyclomatrix phosphazene-containing polyester polymers were synthesized through the reaction of a polyhydroxylated cyclotriphosphazene and a bifunctional acid chloride. To demonstrate the chemistry of the free hydroxyl of hexa-[3-tertbutyl-4-hydroxyphenoxy] cyclotriphosphazene, nucleophilic displacement reactions were performed with both acetic anhydride and alkyl chlorides. This work compares favorably to literature data for the chemistry of hexa- [4-hydroxyphenoxy] cyclotriphosphazene, whose hydroxyl is not hindered by an adjacent substituent. The hindered site of hexa- [3-tert-butyl-4-hydroxyphenoxy] cyclotriphosphazene was found to react with bidentate acid chlorides to yield new high polymers. The phosphazene-containing polyesters were observed to have good solubility in polar organic solvents. Characterization of these new materials was performed using dilute solution laser Light scattering techniques, thermal analysis, and NMR spectroscopy.