Although　lithium-sulfur　(Li-S)　batteries　have　attracted　strong　consideration　regarding　their　fundamental　mechanism　and　energy　applications,　the　inferior　cycling　performance　and　low　reaction　rate　caused　by　the　“shuttling　effect”　and　the　sluggish　reaction　kinetics　of　lithium　polysulfides　(LiPSs)　impede　their　practical　application.　In　this　work,　graphitic　C3N4　(g-C3N4)　assembled　with　highly-dispersed　nitrogen-containing　carbon　quantum　dots　(CQDs)　is　designed　as　a　cooperative　catalyst　to　accelerate　the　reaction　kinetics　of　LiPS　conversion,　the　precipitation　of　Li2S　during　discharging,　and　insoluble　Li2S　decomposition　during　the　charging　process.　Meanwhile,　the　introduction　of　CQDs　improves　the　conductivity　of　the　g-C3N4　substrate,　showing　great　significance　for　the　construction　of　high-performance　electrocatalysts.　As　a　result,　the　as-obtained　composite　shows　efficient　adsorption　and　electrochemical　conversion　of　LiPSs,　and　the　Li-S　batteries　assembled　with　CQDs/g-C3N4　exhibit　an　initial　specific　capacity　of　1300.0　mA　h　g−1　at　the　current　density　of　0.1C　and　retain　582.3　mA　h　g−1　after　200　cycles.　The　electrode　with　the　modified　composite　displays　a　greater　capacity　contribution　of　Li2S　precipitation　(175.7　mA　h　g−1),　indicating　an　enhanced　catalytic　activity　of　g-C3N4　decorated　by　CQDs.　The　rational　design　of　CQDs/g-C3N4　as　a　sulfur　host　could　be　an　effective　strategy　for　developing　high　performance　Li-S　batteries.　©　2024　The　Royal　Society　of　Chemistry.