Although　transition-metal-catalyzed　direct　arylation　of　aromatic　C-H　bonds　is　one　of　the　most　efficient　ways　for　the　construction　of　biaryl　targets,　it　is　also　expected　for　other　alternative　methods　that　can　use　inexpensive　catalysts　and　abundant　solar　energy　to　drive　chemical　reactions.　Herein,　we　describe　a　new　activation　mode　for　biaryl　synthesis　by　using　a　photosensitive　complex　of　potassium　tert-butoxide　(KOt-Bu)　and　nitrogenous　heterocyclic　ligands　via　visible　light　excitation.　Under　low-energy　visible　light　irradiation,　the　single-electron　transfer　from　electron-donor　KOt-Bu　to　electron-deficient　nitrogenous　heterocycle　occurred　in　the　inner　part　of　the　complex　by　using　potassium　as　a　bridge　atom.　The　ligand　accepted　the　as-photoexcited　single　electron　and　transformed　into　stable　radical　anions　which　played　a　dominant　role　in　the　coupling　reactions　of　benzene　with　aryl　halides　at　ambient　temperature.　This　reaction　paradigm　features　the　use　of　inexpensive　catalyst,　abundant　visible　light　energy,　and　more　accessible　bromobenzene　for　the　construction　of　biaryl　compounds　under　rather　mild　conditions.