The　application　of　fluorescent　graphitic　carbon　nitride　(g-C3N4)　nanomaterials　was　limited　by　short　photoluminescence　(PL)　wavelength.　It　is　great　desirable　to　develop　g-C3N4　nanomaterials　with　long　PL　wavelength　and　high　quantum　yield　to　expand　their　application.　Herein　phenyl-modified　and　sulfur　doped　g-C3N4　(PhCNS)　powders　with　tunable　PL　peak　from　520　to　630　nm　were　prepared　by　copolymerization　of　2,4-diamino-6-phenyl-1,3,5-triazine　and　trithiocyanuric　acid.　The　copolymerization　process　of　PhCNS　powders　was　proposed　after　chemical　structure　characterization　and　PL　mechanism　of　PhCNS　powders　were　investigated　by　transient　fluorescence.　In　virtue　of　tunable　PL　color,　broad　PL　peak,　and　high　quantum　yield,　PhCNS　powders　were　utilized　to　fabricate　green,　yellow,　and　white　light-emitting　diodes　with　high　color　quality　and　PhCNS　nanosheets　were　applied　for　multicolor　bioimaging.　This　work　provides　a　pathway　for　exploring　g-C3N4　nanomaterials　with　long　PL　wavelength　and　facilitates　their　application　in　biocompatible　optoelectronic　devices,　fluorescent　bioimaging.　Copyright　©　2020　American　Chemical　Society.