The　direct　reduction　of　inert　planar　arenes　and　heteroarenes　with　visible　light　remains　rarely　explored,　as　the　energy　of　one　visible-light　photon　is　unable　to　overcome　the　stabilization　of　aromatics.　Here　we　report　a　system　based　on　boron　carbonitride　semiconductor,　which　can　reduce　arenes　and　heteroarenes　in　water　under　blue　light　irradiation.　The　system　features　the　advantage　of　low-cost,　high-efficiency,　facile　separation,　benign　environmental　profile　and　broad　substituent　tolerance.　The　methodology　can　be　extended　to　late-stage　functionalization　and/or　deuteration　of　drugs,　hormones　and　axially　chiral　compounds　with　conserved　chirality.　Moreover,　gram-scale　synthesis　is　successfully　implemented　with　catalyst　recycling.　Mechanistic　investigations　support　a　consecutive　blue-light-induced　energy　and　electron　transfer　process,　which　accumulates　sufficient　energy　to　reduce　arenes　to　arene　anions　by　absorbing　two　photons　successively.　The　metal-free　system　introduces　a　simple　and　sustainable　reactivity　mode　for　semiconductor　photocatalysts　and　enriches　the　chemical　toolkit　for　a　class　of　demanding　and　valuable　organic　transformations.　[Figure　not　available:　see　fulltext.].　©　2022,　The　Author(s),　under　exclusive　licence　to　Springer　Nature　Limited.