Lithium-sulfur　(Li-S)　batteries　have　attracted　considerable　attention　due　to　high　theoretical　specific　energy　and　environmental　friendliness.　However,　the　shuttle　of　lithium　polysulfides　(LiPSs)　has　become　a　major　obstacle　for　developing　Li-S　batteries.　In　this　work,　we　explored　a　new　C4N4　monolayer,　which　could　be　easily　prepared　from　its　bulk　form　using　a　similar　mechanical　exfoliation　approach　to　that　of　graphene　due　to　its　smaller　exfoliation　energy.　The　C4N4　monolayer　could　suppress　the　shuttling　of　LiPSs　and　produce　significant　improvement　in　the　cycling　performance　of　Li-S　batteries.　Moreover,　adsorption　calculations　revealed　that　polysulfide　captured　by　C4N4　was　chemisorbed　with　a　suitable　range　of　adsorption　energies　from　-1.931　to　-3.119　eV.　Furthermore,　excellent　surface　diffusions　of　LiPSs　on　C4N4　resulted　in　a　fast　charge/discharge　rate.　Moreover,　to　improve　the　electrical　conductivity　of　C4N4,　graphyne　was　selected　to　construct　a　C4N4/graphyne　heterostructure.　Based　on　these　remarkable　results,　we　conclude　that　C4N4　is　a　highly　promising　anchoring　material　for　Li-S　batteries.　We　hope　that　our　studies　will　inspire　more　experimental　and　theoretical　studies　on　exploring　the　potential　of　other　2D　nanostructures　as　lithium-sulfur　battery　hosts.