It　is　fascinating　yet　challenging　to　assemble　anisotropic　nanowires　into　ordered　architectures　of　high　complexity　and　intriguing　functions.　We　exploited　a　facile　strategy　involving　oriented　etching　of　a　metal-organic　fragment　(MOF)　to　advance　the　rational　design　of　highly　ordered　nanostructures.　As　a　proof　of　concept,　a　microscale　MIL-68(In)　single　crystal　was　etched　with　a　K3[Co(CN)6]　solution　to　give　a　microtube　composed　of　aligned　MIL-68(In)　nanorods.　Annealing　such　a　MIL-68(In)　microtube　readily　created　an　unprecedented　branched　In2O3　mesocrystal　by　assembly　of　In2O3　nanorods　aligned　in　order.　The　derived　ordered-In2O3-ZnIn2S4　is　more　efficient　in　catalyzing　visible-light-driven　H2　evolution　(8753　μmol　h-1　g-1)　outperforming　the　disordered-In2O3-ZnIn2S4　counterpart　(2700　μmol　h-1　g-1)　as　well　as　many　other　state-of-the-art　ZnIn2S4-based　photocatalysts.　The　ordered　architecture　significantly　boosts　the　short-range　electron　transfer　in　an　In2O3-ZnIn2S4　heterojunction　but　has　a　negligible　impact　on　the　long-range　electron　transfer　among　In2O3　mesocrystals.　The　density　functional　theory　(DFT)　calculation　reveals　that　the　oriented　etching　is　achieved　by　the　selective　binding　of　the　[Co(CN)6]3-　etchant　on　the　(110)　plane　of　MIL-68(In),　which　can　drag　the　In　atoms　out　of　the　framework　in　order.　Our　findings　could　broaden　the　technical　sense　toward　advanced　photocatalyst　design　and　impose　scientific　impacts　on　unveiling　how　ordered　photosystems　operate.　©