Heptazine　units　with　highly　rich　nitrogen　sites　were　employed　to　fabricate　a　new　porous　organic　polymer　(POP-HE)　via　direct　coupling　of　2,5,8-trichloro-s-heptazine　and　4,4′,4″,4‴-(ethene-1,1,2,2-tetrayl)tetraaniline　with　the　mild　base　N,　N′-diisopropylethylamine　(DIPEA)　in　tetrahydrofuran　(THF)　solution.　POP-HE　displays　good　CO2　uptake　capacity　(50.6　cm3　g−1,　10　wt%,　1　bar/273　K)　and　highly　selectively　adsorptive　separation　of　CO2　over　CH4　under　ambient　conditions.　Impressively,　at　273　K,　the　predicted　IAST　selectivity　of　POP-HE　is　47.0-13.4　for　the　natural　gas　mixture　(CO2/CH4　=　5:95)　at　pressures　varying　from　0　to　1　atm.　Meanwhile,　the　result　of　calculated　band　gap　value　based　on　Tauc　plot　motivated　us　to　investigate　its　photocatalytic　activity.　POP-HE　was　applied　as　heterogeneous　photocatalyst　for　visible　light-induced　selective　oxidation　of　benzyl　alcohol　to　benzaldehyde,　and　exhibited　great　conversion　of　33.6%　under　irradiation　of　white　LED　light,　which　is　much　higher　than　that　of　g-C3N4.　Moreover,　POP-HE　can　be　recycled　up　to　three　times　without　significant　decrease　in　catalytic　activity.　©　2019　Elsevier　Inc.