The reaction of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) with 6-methoxy-3-methylbenzofuran gave carbon–oxygen adduct. The reaction in less polar solvents such as benzene and CH2Cl2 proceeds faster than that in more polar solvents such as THF and dioxane. In contrast, the reaction of DDQ with indoles gave carbon–carbon adducts. This reaction proceeds rapidly with increasing solvent polarity.