The present study is based on the interaction of diazotized 4-amino-6-chloro-1,3-benzene disulphonamide (DACBS) with 8-hydroxyquinolines in slightly alkaline medium and with dibenzazepines in strongly acidic medium to form red coloured products in the range of 500- 555 nm. Under optimum reaction condition, Beer's law is obeyed in the concentration range 0.5-25 μg/ml for 8-hydroxyquinolines and 1.0-25 μg/ml for dibenzazepines. The stoichiometry of the reaction was investigated and was found to be 1:1 for all the studied drugs. Interference due to other co-formulated drugs, common additives and excepients was studied. The proposed method was applied successfully for the determination of the cited drugs in their pharmaceutical preparations and results were comparable with that of the official, reported method.