Parallel alignment of electric and magnetic transition dipole moments in chiral additives can boost the oxygen evolution reaction.

Homochirality, the uniformity in single molecular handedness, is a defining feature of life. Although universal in biology, the evolutionary advantage of selecting one enantiomer over its mirror image remains unresolved. One possible clue may lie in catalysis itself: recent studies demonstrate that oxygen evolution reaction (OER), a key step in photosynthesis, is sensitive to chirality. Here, we report that electrochemical OER performance with chiral additives may be correlated to the alignment of their electric (ETDM) and magnetic (MTDM) transition dipole moments in the lowest-energy transition. Enantiomers with parallel ETDM-MTDM configurations consistently outperform their antiparallel counterparts. Notably, this bias also manifests in natural systems, suggesting a shared stereoelectronic principle. We define this stereoelectronic correlation as the Supplementary Angle Effect (SAE). Our findings establish SAE in electrocatalysis offering a quantitative descriptor for assessing how molecular handedness affects catalytic behavior and enantiodifferential performance.