Biodegradable and economically viable choline chloride-FeCl 2. H 2 O deep eutectic solvent (DES), was synthesized and successfully utilized as a catalyst and reaction medium for the selective oxidation of aromatic methyl groups to aldehydes. To demonstrate the synthetic potential of this protocol, the reaction was scaled up to the gram scale. The DES could be reused up to four times without considerable effect on the yield of the reaction. The key features of the protocol that qualify the process as green include the ambient reaction temperatures, easy isolation of the products, higher yields, recyclability of the catalyst, and reactions without the use of conventional organic solvents.