Seeking　highly-efficient,　non-pollutant,　and　chemically　robust　photocatalysts　for　visible-light-driven　ammonia　production　still　remained　challenging,　especially　in　pure　water.　The　key　bottle-necks　closely　correlate　to　the　nitrogen　activation,　water　oxidization,　and　hydrogen　evolution　reaction　(HER)　processes.　In　this　study,　a　novel　Bi　decorated　imine-linked　COF-TaTp　(Bi/COF-TaTp)　through　N–Bi–O　coordination is reasonably　designed　to　achieve　a　boosting　solar-to-ammonia　conversion　of　61　µmol−1 g−1 h−1　in　the　sacrificial-free　system.　On　basis　of　serial　characterizations　and　DFT　calculations,　the　incorporated　Bi is conducive　to　the　acceleration　of　charge　carriers　transfer　and　N2　activation　through　the　donation　and　back-donation　mode.　The　N2　adsorption　energy　of　5%　Bi/COF-TaTp is calculated　to　be　−0.19 eV　in　comparison　with　−0.09 eV　of　the　pure　COF-TaTp　and　the　electron　exchange　between　N2　and　the　modified　catalyst is much　more　intensive.　Moreover,　the　accompanied　hydrogen　production　process is effectively　inhibited　by　Bi　modification,　demonstrated　by　the　higher　energy　barrier　for　HER　over　Bi/COF-TaTp　(2.62 eV)　than　the　pure　COF-TaTp　(2.31 eV)　when　using　H　binding　free　energy　(ΔGH*)　as　a　descriptor.　This　work　supplies　novel　insights　for　the　design　of　photocatalysts　for　N2　reduction　and　intensifies　the　understanding　of　N2　adsorption　and　activation　over　covalent　organic　frameworks-based　materials.　©　2022　Wiley-VCH　GmbH.