A study of the electro-optic characteristics of azobenzene derivations waspresented,and these materials have been doped in the PVK. The electro-optic coefficient of PVK-azobenzene thin film has been measured by an electro-optic modulation method.Theelectrooptic coefficient of the PVK thin film doped with 15% (weight ratio) nitroazobenzene is as high as 13.4 pm/V. The photorefractivity was observed in anitroazobenzene doped organic composite containing polyvinylcarbazole' and a photosensitizeras well as a fullerene (C60).