<p>Organic-based corrosion inhibitors often exhibit limited protonation and suboptimal inhibition efficiencies when used individually in neutral corrosion environments. However, the combination of various organic molecules in a formulation can yield significant synergistic effects. Crude extracts from plant biomass represent an affordable, environmentally friendly, and abundantly available source of organic corrosion inhibitors. Thus, identifying plant extracts with high efficiency continues to be a pressing necessity. In this study, we explored the crude extract of <i>Chrysophyllum albidum</i> leaves as a potentially effective inhibitor for the corrosion of a Cu-Ni (70–30) alloy immersed in a neutral 3.5% NaCl solution. Through gravimetric, electrochemical, and computational analyses, we found that the inhibition efficiency improved with increasing extract concentration and prolonged immersion times, although it slightly decreased at higher temperatures. After 72&#xa0;h of immersion at 25&#xa0;°C, a concentration of 1200&#xa0;ppm of the extract achieved an impressive efficiency of 90.07%, functioning as a mixed-type inhibitor and interacting with the substrate obeying the Langmuir isotherm with an R² value of 0.9997. This was further supported by results from RDF (3.19 Å to 10.2 Å), activation energy (37.77&#xa0;kJ/mol to 34.64&#xa0;kJ/mol), heat of adsorption measurements (-1.06 to -2.09), and thermodynamic results derived from Eyring plots. However, increasing the temperature to 90&#xa0;°C resulted in a reduction of efficiency. GC–MS and FTIR analysis revealed that the extract contains O and N heteroatoms. Additionally, computational modeling indicated that these heteroatoms serve as adsorption sites for interaction with the substrate, with the spontaneous nature of the adsorption evidenced by a significantly negative energy value of -436.64&#xa0;kJ/mol.</p> Graphical Abstract <p></p>