<p>Arrangement of atoms in compounds leads to a variety of products (isomers), which can exhibit different responses due to physical and chemical vulnerabilities. Measuring the vulnerability of such isomers of single compound using cost-effective methodologies are embracing. Forgoing-in-view, an attempt has been made to distinguish between two positional isomers, o-Coumaric acid (o-CA) and p-Coumaric acid (p-CA) based on their perturbation effects using a novel Briggs-Rauscher (BR) electrochemical oscillating system (H₂SO₄–CH₂(COOH)₂–KI–H₂O₂ &amp; tetra-aza-macrocyclic Ni-Complex catalyst ([NiL](ClO₄)₂) is proposed in this article. The ligand “L” in [NiL](ClO₄)₂ is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene which is highly vulnerable to external perturbation due the presence of pi-bond. Experimental results show that adding equal amounts of the same concentrations of o-CA &amp; p-CA separately into the active BR electrochemical oscillator could temporarily cease the oscillations, which then regenerate after inhibition time (t_in). However, the t_in caused by the o-CA is longer compared to the t_in initiated by p-CA. Moreover, when t_in was plotted against the concentrations of o-CA &amp; p-CA, two distinct linear regression curves were obtained for these isomers over the concentration range of 2.3 × 10^–5&#xa0;mol L⁻¹ ~ 2.5 × 10^–4&#xa0;mol L⁻¹, with a correlation coefficient of 0.98, clearly demonstrating the different behaviors of these isomers. Thus, the isomers were successfully distinguished. A mechanistic approach based on Furrow-Cervellati-Amadori (FCA) and Noyes-Field (NF) models was designed and justify the ceasing and regeneration of typical oscillations due to perturbation. Briefly, the intermediate species, HOO^⋅ (hydroperoxyl radical), produced during the course of oscillatory reactions, oxidizes additives into their respective quinones.</p> Graphical abstract <p></p>