Non-oxidative ethane dehydroaromatization to form aromatic hydrocarbons was investigated over various metal supported on H-ZSM-5 catalysts. Co/H-ZSM-5 prepared using an ion-exchange (IE) method exhibited high catalytic performance with a small amount of carbon deposition. Results obtained from temperature-programmed reduction and X-ray absorption fine structure spectroscopy indicate that stable Co2+ cations exist on Co/H-ZSM-5 IE during the reaction. Co2+ cations efficiently activate ethane without coke formation.