Background Safinamide, a highly specific inhibitor of monoamine oxidase B, is a new approved prodigious therapy used to cure Parkinson's disease (PD). Objective Before marketing and selling a medicine, manufacturers must guarantee that the manufacturing process is consistent by monitoring levels of process-related chemicals and drug contaminants. Therefore, five precise, fast, and accurate spectrophotometric techniques were employed and evaluated for the simultaneous measurement of safinamide and its synthetic precursor, 4-hydroxybenzaldehyde. Methods The first derivative, derivative ratio, ratio difference, dual wavelength, and Fourier self-deconvolution methods worked well to resolve spectral overlap of safinamide and its synthetic precursor, 4-hydroxybenzaldehyde. Results Safinamide detection limits ranged from 0.598 to 1.315 µg/mL, whereas the 4-hydroxybenzaldehyde detection limit was found to be as low as 0.327 µg/mL. Conclusion According to International Council for Harmonisation (ICH) criteria, all procedures were verified and confirmed to be accurate, robust, repeatable, and precise within reasonable range. No considerable variation was found when comparing the outcomes of the suggested approaches to the findings of previously published methods. The ecological value of established methods was measured: the national environmental methods index (NEMI), the analytical eco-scale, the analytical greenness metric (AGREE), and the green analytical process index (GAPI) were used. Highlights This is the first spectrophotometric determination of safinamide drug in the presence of its synthetic precursor. Five simple and efficient spectrophotometric approaches were employed to determine a newly approved antiparkinsonian drug in the presence of its synthetic precursor simultaneously. Ecological appraisal was performed for the developed methods using four assessment tools.