Poly(p-oxybenzoate) (PpOBA) has been polymerized in the bulk at temperatures below the melting point of the monomer. Polymerization involves, isothermally, sublimation-recrystallization-melting (chemical reaction)-polymerization-liquid crystal domain formation-crystallization processes. Lamellae, about 100 angstrom thick for PpOBA, are observed along with particulate material. D.s.c. and FTi.r. scans indicate that the sublimate is identical to the monomer, but that the ’melt’ has undergone some esterification. The polymer produced is of relatively low molecular weight, but the degree of polymerization can be rapidly increased by heating to elevated temperatures.