A highly efficient method for the C–C bond formation via molecular iodine-catalyzed C3- alkylation reaction of 4-hydroxycoumarins with benzylic, benzhydrylic, allylic, and propargyl alcohols at 50° C in MeNO2 is described. The 3-alkylated-4-hydroxycoumarins were obtained in good yields (up to 97%). By applying this reaction as the key step, a multi- substituted pyranocoumarin can easily be synthesized in a one-pot procedure. The ...