We prepared the heterocyclic nonlinear optical chromophores that contain phenothiazine conjugative bridge between an electron donor and acceptor. Electrochemical analysis and absorption spectroscopic study were performed to investigate the molecular energy states of phenothiazine- based chromophores. Electrooptic properties of guest- host systems in amorphous polycarbonate ( APC) were investigated by optimizing poling conditions. 52pm/V of a maximum r(33) was obtained in the APC sample bearing 31 wt% of highly conjugated chromophore, 6 at 1.3 mu m and it also displayed good thermal stability.