Electrochemical oxidation of catechols (1a-d) has been studied in the presence of 2-thiazoline-2-thiol (3) as a nucleophile in aqueous solution, using cyclic voltammetry and controlled potential coulometry. The results indicate that the quinones derived from catechols (1a-d), participate in Michael addition reactions with 2-thiazoline-2-thiol and via an EC mechanism pathway, convert to the corresponding catechols derivatives (4a-d and 4'd). The electrochemical synthesis of compounds (4a-d and 4'd) has been successfully performed at a carbon rod electrode and in an undivided cell with good yield and high purity. The products have been characterized by IR, 1H NMR, 13C NMR and MS.