Disperse Red-1 type chromophores were attached to the backbones of PMMA, polyvinyl-phenol as well as the styrene-Maleimide alternative copolymer and glass transition temperatures of these three polymer derivatives were in the range of 125, 165, and 245°C, respectively. We have also, for the first time, attached EO chromophores to some thermostable cardo-polymers. Fluorene derivatives in which the 2- and 7-positions were substituted with an electron accepting and an electron donating substitutem, respectively, were made polymerizable through their reactive functional groups at the 9,9′-positions. Various condensation polymers were prepared. These polymers are amorphous, film-forming, thermostable, and having Tg ranging from 150 to 300°C. These polymers exhibit strong electro-optic properties after electrode poling. Thermal stabilities of these polymers were compared by following the spectral decay of the chromophore and the decay of the electro-optic coefficient. The loss of EO activity at elevated temperature can be realized as a combination of chromophore reorientation and chemical degradation.