The electrochemical behavior of 1,5-diaminonaphthalene (1,5DAN) was studied by cyclic voltammetry and controlled-potential coulometry methods in aqueous ethanol (water/ethanol, 70/30 v/v). The effect of different parameters such as solution pH (from 2 to 10), potential scan rate and 1,5DAN concentration on its electrochemical behavior was studied. The electrochemical synthesis of 4-imino-4H-dibenzo[a,h]phenoxazin-11-ol (IDP) was achieved in high yield (87%) by electrooxidation in water (bicarbonate buffer, c = 0.2 M, pH = 9.0)/ethanol (70/30, v/v) in a one-pot process. The proposed mechanism involves the Michael addition of 1,5DAN to 1,5-naphthalendione (from the hydrolysis of the electrogenerated naphthalene-1,5-diimine (1,5DAN(ox))) followed by oxidation of the 1,5-diaminonaphthalene moiety, cyclization, aromatization, and a final oxidation. Polymerization of 1,5DAN was not observed. The present work provides a green and environmentally friendly method with high atom economy for the synthesis of IDP in an undivided cell under constant current. In addition, IDP showed antibacterial activity against Gram-positive bacteria Bacillus cereus and Staphylococcus aureus. (C) 2017 The Electrochemical Society. All rights reserved.