Abstract Condensation of 4-bromo-(4) and 4-nilro-l, 8-naphthalimides (5) with 2- aminobenzenethiol gave 4-(2-aminoulicnylthio)-1, 8-naphthalimides (7). Cyclisalion of 7 by the: Pschorr reaction afforded benzo [k, l] thioxanthene-3, 4-dicarboximides (8), also obtained by reaction ol amities with benzo [k, l] thioxanthene-3, 4-dicarboxylie anhydride (11).