Abstract: In this paper, the interaction between the excited carbazole and chloro-alkanes has been studied. Photochemical reaction in these systems has been proved by the emission, excitation spectra and the color change in the carbazole and chloro-alkane solution mixed with dimethyl yellow after illumination. The photochemical reaction may proceed through the formation of exciplex which can be verified by quenching and phosphoreoe-nce. A reaction mechanism at the initial gtage has been suggested.