In our study of organic molecules for OLED, we have paid attention to 4,4'-bis(N-carbazolyl)biphenyl (CBP), an arylamine commonly used as phosphorescent host or hole transport material in OLED, and performed photochemical and photocatalytic experiments. For the photocatalytic experiment, heterogeneous mixture of CBP and TiO2 powder (Degussa P25) in tetrahydrofuran solution has been placed under UV radiation. Both photochemical and photocatalytic experiments have resulted in degradation of CBP, however, with widely different rates and degradation products. With ever increasing demand for high performance OLEDs, higher stability and longer lifetime of their organic components are essential. In this respect, current informations are sure to be valuable in the design and operation of OLEDs as well as arylamine-based OLED.