As　one　of　the　most　direct　methods　to　construct　molecular　scaffolds　in　fine　chemicals,　C-H　bond　oxidation　is　a　hot　research　area　in　catalysis.　One-dimensional　covalent　organic　frameworks　(1D-COFs)　developed　recently　have　attracted　growing　attention　for　catalytic　applications　owing　to　their　unique　edge　microstructure.　Herein,　a　novel　crystalline　1D-COF　(FZU-66)　was　constructed　and　further　decorated　with　cobalt(II),　which　led　to　excellent　heterogeneous　catalytic　performance　in　the　C-H　bond　oxidation　of　ethylbenzene.　In　an　aqueous　solution　at　room　temperature　within　16　h,　the　conversion　is　nearly　100%,　while　the　acetophenone　selectivity　is　around　99%.　More　impressively,　the　designed　single-dispersed　cobalt(II)-coordinated　1D-COF　(FZU-66-Co)　retained　good　catalytic　activity　while　maintaining　high　crystallinity　after　at　least　five　consecutive　recycling　experiments.　This　work　will　prompt　the　application　of　porous　polymers　in　the　catalyzed　oxidation　of　C-H　bonds　and　make　it　an　efficient　and　sustainable　platform　for　activating　C-H　bonds　of　aromatic　hydrocarbons.　©　2024　American　Chemical　Society.