Three 2-substituted thiazolo[5,4-a]acridin-11 (6H)-ones and seven 11-thioxo
-, 11-alkylimino-, and 11-phenoxythiazolo[5,4-a]acridines have been prepare
d. All these new acridines obtained in good yields have an angularly fused
ring system, which has been determined by H-1- and C-13-NMR spectral data.