AbstractThe reaction product ofm‐cresol and phosphorus pentoxide has been shown by31P‐nmr to consist of an equimolar mixture of mono‐ and di‐m‐cresyl phosphate. A mixture of pure di‐m‐cresyl phosphate andm‐cresol is an excellent polymerization medium for the preparation of polyquinolines via the Friedländer reaction, giving higher‐molecular‐weight polymers than can be obtained from the crude reaction ofm‐cresol and phosphorus pentoxide. Spin‐lattice relaxation timesT1have been used to relate the chain mobility of the polymers in solution to the glass transition tempe