A process for the production of an aromatic azo compound having a 2,3-dihydrobenzofuran ring bearing a diazo group at the 5-position of the ring by conducting the diazo coupling of a 2,3-dihydrobenzofuran derivative represented by the general formula (II): [wherein R1 and R2 are each independently C1-6 alkyl; R3 is optionally substituted aryl; and R4, R5 and R6 are each independently hydrogen, C1-6 alkyl, halogeno, C1-6 alkoxy, or C1-6 alkylthio] with a benzenediazonium salt having an electron-withdrawing group at the p- and/or o-position in a mixed solvent composed of water and a polar organic solvent.