2‐oxo‐2H‐chromen‐7‐olate catalyzed C–C and C–N Bond Formations in Visible Light

7‐hydroxycoumarin is a naturally occurring compound with useful biological and fluorescent properties. In this work, we demonstrate a base‐assisted photoactivation of 7‐hydroxycoumarin in blue LED and its potential in enabling C‐C and C‐N bond formations. 7‐hydroxycoumarin, on deprotonation with Cs2CO3 forms 2‐oxo‐2H‐chromen‐7‐olate which exhibits photoreductant properties and mediates arylation and hydroxyarylation using hypervalent iodonium ylides; alkylation using N‐hydroxyphthalimide esters; and amination with primary and secondary amines. The strategy does not require any additional metal or organic dye‐based photocatalyst and offers a good functional group tolerance giving the products in moderate to good yields in short reaction time.