The room-temperature phosphorescence (r.t.p.) and fluorescence spectra of benzoquinoline isomers are investigated. The isomers can be resolved into the linear or angular subgroups on the basis of their fluorescence and r.t.p. spectra by using conventional fixed excitation. Second-derivative and synchronous scanning techniques can be combined to improve the selectivity of the r.t.p. and fluorescence methods. These simple luminescence techniques were used to estimate three benzoquinoline isomers in a coal tar fraction. Direct analysis of this complex sample allowed acridine to be estimated and upper limits to be provided for benzo(h)quinoline and phenanthridine; the presence of three other isomers was not detected. Comparative studies with data obtained by high-performance liquid chromatography are reported. © 1985.