In this work, four time-saving, economic, and non-sophisticated spectrophotometric methods are used to determine resorcinol (RES) and catechol (CAT) in their binary solutions. The suggested methods, which require no separation steps, are namely the constant center (CC), ratio difference (RD), H-point standard addition method (HPSAM), and ratio H-point standard addition method (RHPSAM). For each method, the parameters affecting the resolution of the spectra are optimized and used for the quantification of RES and CAT in a blind binary mixture. The results obtained show that out of these four original mathematical techniques, the CC and RD methods have the least errors in the simultaneous determination of RES and CAT in their binary solution with a highly severe overlapping spectra. The calibration curves have a linear behavior over the concentration range of 2.5-20 μg/mL for both substances in both methods. The detection limits for RES are 0.89 μg/mL and 0.355 μg/mL for the CC and RD methods, respectively, and for CAT, they are 0.582 μg/mL and 0.292 μg/mL, respectively. The accuracy and precision of the methods are also investigated. The relative standard deviations have been found to be lower than 6.7 %.