density functional theory (DFT) calculations. The quasi-reversible cyclic voltammogram of dioxygen/O2 •-was modified by the presence of trans-resveratrol, suggesting that the electrogenerated O2 •-was scavenged by trans-resveratrol through proton-coupled electron transfer (PCET) via three phenolic hydroxy groups (OH) on the stilbene moiety. The reactivity of trans-resveratrol toward O2 •-characterized by the OHs was experimentally confirmed in comparative analyses using some related compounds in DMF. The electrochemical and DFT results suggested that a concerted PCET mechanism via 4'OH of trans-resveratrol proceeds, where the coplanarity of the two phenolic rings in the stilbene moiety linked by an ethylene bridge is essential for a successful O2 •-scavenging.