Disclosed is the synthesis procedure for benzazolo[3,2-a]quinolinium chloride salts and the inclusion of chloro-substituent, amino-substituent, and nitro-substituent resulting in several compounds. The compounds are further used as markers due to their fluorescent properties including in hypoxic environments.This disclosure further describes anti-cancer screening of two BQS, namely, 7-benzyl-3-aminobenzimidazo[3,2-a]quinolinium chloride (ABQ-48: NSC D-763307) and the corresponding 7-benzyl-3-nitrobenzimidazo[3,2-a]quinolinium chloride (NBQ 48: NSC D-763303).
