Under neat conditions,an efficient method for synthesis of imidoesters has been developed using cyanatobenzenes and dicarbonyl compounds.Nucleophilic addition spontaneously occurred between the two kinds of materials at room temperature with yields of up to 90%.A mechanism directed towards to the imidoester formation has been proposed. Under neat conditions, an efficient method for synthesis of imidoesters has been used using cyanatobenzenes and dicarbonyl compounds. Nucleophilic addition spontaneously occurred between the two kinds of materials at room temperature with yields of up to 90%. A mechanism directed towards the imidoester formation has been proposed.