It is the aim of this work to extend the use of phosphorescence as an analytical technique to a number of different classes of drugs and to study any structure-spectral correlations existing between them. Part of the present work is directed towards developing a technique capable of scanning thin-layer chromatograms and measuring the phosphorescence of separated components in situ. The sensitivity of phosphorescence and separatory function of thin-layer chromatography could thus be combined to produce a rapid, sensitive method capable of resolving small quantities of similar compounds, especially drugs and their metabolites, from complex mixtures.