A　catalytic　phenylation　reaction　of　α,β-unsaturated　acylazoliums　with　in-situ-generated　phenolates　was　developed.　A　combination　of　N-heterocyclic　carbene　and　potassium　ion　cooperatively　catalyzed　the　generation　of　α,β-unsaturated　acylazoliums　and　phenolates　from　α,β-unsaturated　phenolic　esters　for　the　efficient　[3+3]　annulation,　which　involves　a　dearomatization–rearomatization　process.　The　approach　gives　good　yields　and　excellent　regioselectivities,　and　the　products　could　be　easily　converted　into　high-value　polycyclic　derivatives.　Mechanistic　studies　demonstrated　that　the　potassium　ion　plays　a　vital　role　in　this　reaction.　©　2016　WILEY-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim