Abstract: The oxidative demethylation of 1, 4-dimethoxynaphthalene and 1, 4- dimethoxybenzene derivatives with cobalt (III) fluoride proceeded in good to excellent yield to afford the corresponding naphthoquinone and benzoquinone derivatives. Key words: oxidative demethylation, cobalt (III) fluoride, hydroquinone dimethyl ethers, quinones, reduction potential