Due to the high toxicity of phenols, the World Health Organization (WHO) recommended that, the maximal acceptable phenol content in drinkable water should be less than 0.001 μg/mL. This article aims to employ the first ratiometric probe as a luminescent probe to detect the phenol in industrial effluents. Under optimal operating parameters, the quenching of the luminescence intensity of the chemosensor is directly proportional to the concentration of phenol in the range of 1.4 to 8.6 µg/mL, The limit of detection (LOD) is 1.2 µg/mL using ratiometric fluorescence. Moreover, the method was applied successfully for the detection of phenol in real industrial effluents with satisfied recovery and validated by standard method (4-AAP) to yield very closely similar concentrations of both methods. Therefore, this method can help for a simple quality control of total phenol content in industrial effluents. Based on these studies, future work will be carried out to establish the accuracy and selectivity of the fiber-optic sensors.