Exploiting　efficient　photocatalysts　with　strengthened　structure　for　solar-driven　alcohol　oxidation　is　of　great　significance.　The　photocatalytic　performance　of　graphitic　carbon　nitrides　can　be　considerably　promoted　by　modulating　its　crystallinity.　Results　confirmed　that　a　high　crystallinity　accelerates　the　separation　and　transfer　of　photogenerated　charge　carriers,　thus　providing　more　free　charges　for　photoredox　reactions.　More　importantly,　the　high　crystallinity　facilitated　the　adsorption　of　benzyl　alcohol　and　desorption　of　benzaldehyde　and　simultaneously　lowered　the　energy　barrier　for　O2　activation.　As　a　result,　the　crystalline　carbon　nitride　exhibited　a　roughly　twelvefold　promotion　with　respect　to　the　normal　carbon　nitride.　The　remarkable　enhancement　of　activity　can　be　attributed　to　the　synergistic　effects　of　increased　electron–hole　separation　and　increased　surface　reaction　kinetics.　These　findings　will　open　up　new　opportunities　to　modulate　the　structure　of　polymers　for　a　wide　variety　of　organic　reactions.　©　2017　Wiley-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim