A series of optically active main-chain polyesters were synthesized by high-temperature polycondensation from biphenolic azo chromophores, (2R,3R)-(+)-diethyl tartrate and terephthaloyl chloride. The polyesters showed glass transition temperatures in the range of 100-135degreesC and were thermally stable to 350degreesC. The second harmonic generation efficiency of the polyesters was studied by the powder method and as thin films with 2-methyl-4-nitroaniline as a reference. The SHG efficiency of the polymers was compared with that of low molecular weight chromophores. The polymers with chiral units showed good second harmonic generation efficiency. The SH signal also showed good temporal stability. (C) 2003 Wiley Periodicals, Inc.