An electrochemical tandem cyclization of enaminones with amidines has been reported for the first time using dibromomethane as an initiating agent in an undivided cell. Following this protocol, a vast variety of polysubstituted 5-acylimidazoles were obtained in moderate to good yields without the use of external oxidants. Mechanistic studies indicate that the bromide anion, electroreductively generated from dibromomethane, acts as a redox mediator to complete the catalytic cycle.