Electrochemical chlorine evolution reaction (CER) is one of the most important electrochemical reactions due to widespread importance of Cl₂ as an industrial chemical_. However, electrochemical CER is bridled with parallel of oxygen evolution reaction (OER) reducing the performance of anode towards Cl₂ production. In this context, the guiding principles of enhancing the selectivity of CER is investigated experimentally and computationally in RuO₂ doped with first-row-transition-metals. Computational studies suggest that low-valent dopant (Cu, Zn) tend to surface segregate and they tend to weaken the interaction of adsorbates with the surface. Further, doping of metals having higher d-electrons than Ru in RuO₂ tend to lower the binding strength of OER intermediates (e.g. HO-, O-, HOO-) thereby increasing its overpotential . However, doping have less effect on the binding strength of monovalent CER intermediates (e.g. ClO-, Cl-) resulting in higher CER selectivity. Computational studies suggest that Cu (d⁹)-doped RuO₂ would show maximum CER selectivity and this has been corroborated by experiments with electrodeposited doped RuO₂. The electrodeposited Cu-doped RuO₂ (2% dopant concentration) has been found to show 95% CER selectivity at acidic medium. However, doping of d-enriched metals also lower the bridge-oxygen vacancy formation energy which activates lattice-oxygen-vacancy aided water dissociation pathway and aid the selectivity of OER. This may result in an optimum doping concentration wherein maxima of CER selectivity is observed as in case of for Cu- and Zn-doped RuO₂ electrocatalysts experimentally. The present work offers insight on catalyst design taking account of selectivity of CER and OER during electrochemical Cl₂ production.