4′,7′,10′,13′-pentaoxacyclopentadeca)-2′-ene]coumarin (2) was prepared as a new fluorescence derivatization reagent for carboxylic acids in high-performance liquid chromatographic analysis. The derivatization of lauric acid with 2 was readily accomplished under a quite mild condition to yield a highly fluorescent lauric acid derivative. The reaction was accelarated by combining crown moiety as a catalytic