To　develop　a　photocatalyst　with　catalytical　activity　for　substrates　with　low　reactivities　is　always　highly　desired.　Herein,　based　on　the　principle　of　structure-property　relationships,　we　rationally　designed　the　natural　product　cercosporin,　the　naturally　occurring　perylenequinonoid　pigment,　to　develop　a　novel　organic　perylenephotoreductant,　hexacetyl　reduced　cercosporin　(HARCP),　through　structural　manipulation.　Compared　with　cercosporin,　HARCP　shows　prominent　electrochemical　and　photophysical　characteristics　with　greatly　improved　photoreductive　activity,　fluorescence　lifetime　and　fluorescence　quantum　yield.　These　properties　allowed　HARCP　as　a　powerful　photoreductant　to　efficiently　realize　a　series　of　benchmark　reactions,　including　photoreduction,　alkoxylation　and　hydroxylation　to　construct　C-H　and　C-O　bonds　using　aryl　halides　as　substrates　under　mild　conditions,　all　of　which　have　never　been　achieved　by　the　same　photocatalyst.　Thus,　this　study　well　supports　the　notion　that　the　principle　between　structural　manipulation　and　photocatalytic　activity　is　of　great　significance　to　design　customized　photocatalysts　for　photoredox　chemistry.　(c)　2021　Elsevier　Inc.　All　rights　reserved.