CO2　is　a　vital　compond　for　life,　and　its　concentration　significantly　affects　the　living　environment　of　the　Earth.　Extensive　effort　has　been　devoted　to　balance　its　concentration.　Among　the　developed　approaches,　photocatalytic　CO2　conversion　is　considered　as　an　ideal　option.　Previous　reports　suggest　polymeric　carbon　nitride　(PCN)　can　be　effectively　used　as　a　metal-free　photocatalyst　to　convert　CO2.　Herein,　the　recent　developments　of　PCN　and　the　related　photocatalysts　for　CO2　conversion　are　summarized　from　the　fundamental　of　using　PCN,　and　their　extended　applications　through　molecular　modification　and　physical/chemical　coupling　with　other　substances.　The　concluding　remarks　finally　indicate　the　future　challenges　of　using　PCN　materials　for　relevant　solar-driven　applications.　©　2018　The　Royal　Society　of　Chemistry.