The photocatalytic activity of titanium dioxide supported on zeolites HZSM-5, HY and Hbeta was evaluated for a novel intermolecular cyclization of ethylenediamine with propylene glycol leading to dihydropyrazine. Titanium dioxide supported on zeolites has been prepared with 2 and 5 wt% of TiO2 by solid-state reaction, impregnation and sol impregnation methods. From the characterization by XRD, BET, EDAX and TPD of NH3, it is deduced that in all cases titanium dioxide is in small particles of anatase on zeolites. The highest photocatalytic activity was obtained with 2 wt% TiO2/Hbeta prepared by solid-state reaction. The acidity determined by TPD of NH3 was found to be lower for TiO2/Hbeta than for TiO2/HZSM-5 and TiO2/HY. From the above observations, it can be concluded that adsorption, acidity and structure of zeolites have an influence on the activity of supported TiO2.