A study has been made of a novel fluorescent and phosphorescent label 6-coumarinsulphonyl chloride (6-CSCl) based an the coumarin nucleus with a reactive group similar to dansyl chloride. The synthesis, analysis, derivatisation and application of the label to certain analytical problems have been studied. The label was obtained in a high state of purity by a straightforward sulphonation of the counarin nucleus. Characterisation of the label was carried out using mass spectrometry, NMR and IR, its purity was verified by elemental analysis. The label was found to be highly stable and react at room temperature with phenolic and amino groups. The luminescence properties of the label and its derivatives were investigated both at room temperature and at 77K. The room temperature fluorescence showed a strong pH dependence which was not observed at 77K. Environmental effects on the fluorescence properties of the derivatives at room temperature were investigated. Linearity range, quantum yields and the detection limits of the derivatives were determined. The optimum derivatisation conditions for various compounds were determined by HPLC. The analytical applications of the label were investigated by studying the behaviour of the derivatives in HPLC and TLC systems. In the area of HPLC, both pre-c6lumn and post-column derivatisation were attempted. The ion-pair pre-column derivatisation technique was found to be more suitable for this work. TLC analysis was performed on both normal phase and HPTLC plates. The separated components were detected using absorbance and phosphorimetry. Synthesis of the labels with substituents at the 4 and 7 position of the coumarin nucleus were carried out. The behaviour of the modified labels and their derivatives were compared with the original label and its derivatives.