A simple and sensitive spectrophotometric procedure is described for the quantitative determination of certain fluoroquinolones (ciprofloxacin, enoxacin, and norfloxacin) either in authentic samples or in their pharmaceutical formulations. The cited drugs are interacted with a synthetic reagent, N-2,6-dimethylphenyl-2,3-dichloromaleimide forming an intense colour which can be measured at Amax 514 nm. The optimum interaction conditions, molar ratio of the reactants, and calibration graphs have been studied. A comparative study with the official pharmacopoeial methods of assay of the cited drugs showed no significant difference between them. Furthermore, the proposed procedure was more sensitive and selective. Moreover, the reaction product was isolated and subjected to the structural study using IR and NMR spectroscopy.