Reactions of 4-chloro-3-nitrocoumarin with a variety of nucleophiles produced a number of novel substitutedcoumarins. Hard and borderline nucleophiles exclusively substitute chlorine in position 4, while softnucleophilessubstitute the nitro group in position 3 (except for iodide) of the title compound. This result of the nucleophilicsubstitution of 4-chloro-3-nitrocoumarin is rationalized in terms