The　photocatalytic　synthesis　of　hydrogen　peroxide　(H2O2)　from　water　and　oxygen　using　metal-free　catalysts　represents　a　promising　approach　to　H2O2　production,　offering　advantages　in　terms　of　reduced　environmental　impact,　energy　efficiency,　and　enhanced　safety.　Covalent　organic　frameworks　(COFs)　with　imine　linkages　have　emerged　as　a　promising　class　of　materials　for　this　purpose,　given　their　structural　and　functional　diversity.　However,　they　often　suffer　from　poor　durability,　inefficient　photogenerated　charge　separation　efficiency,　and　rapid　recombination　of　photogenerated　electron-hole　pairs.　To　address　these　limitations,　a　linkage　conversion　strategy　in　COFs　can　be　employed　to　improve　both　stability　and　photoactivity.　Herein,　we　demonstrate　the　conversion　of　imine　bonds　into　thiazole　rings,　thereby　facilitating　charge　transfer　and　enhancing　the　photocatalytic　stability　of　COFs.　This　structural　modification　enables　the　thiazole-linked　COF　to　maintain　stable　photocatalysis　over　a　24-h　period,　achieving　an　H2O2　production　rate　of　57.1　µmol/h　(per　10　mg).　This　rate　is　twice　that　of　the　pristine　imine-linked　COF　and　surpasses　those　of　most　metal-free　photocatalysts.　This　investigation　provides　novel　insights　into　the　development　of　advanced　COF-based　photocatalysts　for　photocatalytic　energy　conversions.　(Figure　presented.)　©　Jilin　University,　The　Editorial　Department　of　Chemical　Research　in　Chinese　Universities　and　Springer-Verlag　GmbH　2024.