The rearrangement of 4-substituted azoxybenzenes into hydroxyazobenzenes has been studied by an ultraviolet spectrophotometric method and by isolation of the rearranged compounds. The oxygen atom in the azoxy group migrated to the unsubstituted ring, depending neither on the substituent already present in the other ring, nor on the distance between the oxygen atom and the available position. The position in the open ring, ortho ...