The　valorization　of　native　lignin　to　functionalized　aromatic　compounds　under　visible　light　is　appealing　yet　challenging.　In　this　communication,　colloidal　mercaptoalkanoic　acid　capped　ultrathin　ZnIn2S4　(ZIS)　microbelts　was　successfully　fabricated,　which　was　used　as　a　superior　catalyst　for　depolymerization　of　native　lignin　in　birch　woodmeal　under　visible　light,　with　an　optimum　yield　of　28.8　wt　%　to　functionalized　aromatic　monomers　achieved　in　8　h.　The　capped　mercaptoalkanoic　acid　not　only　enables　a　solvent　modulated　reversible　interchange　of　ZIS　between　the　colloidal　state　for　efficient　reaction　and　the　aggregated　state　for　facile　separation,　but　also　serves　as　a　precursor　for　light　initiated　generation　of　reactive　thiyl　radical　for　highly　selective　cleavage　of　β-O-4　bond　in　native　lignin.　This　work　provides　a　green　and　efficient　strategy　for　the　depolymerization　of　native　lignin　to　functionalized　aromatic　monomers　under　mild　conditions,　which　involves　a　new　mechanism　for　the　cleavage　of　β-O-4　bonds　in　native　lignin.　The　capability　of　cleavage　of　β-O-4　bonds　in　native　lignin　by　photogenerated　thiyl　radicals　also　demonstrates　the　great　potential　of　using　photogenerated　thiyl　radicals　in　organics　transformations.　©　2024　Wiley-VCH　GmbH.