Nanoscale　metal–organic　frameworks　(nano-MOFs)　with　unique　open　architectures　offer　great　advantages　for　constructing　fascinating　functional　materials,　but　their　configurations　are　largely　limited　to　mesoporous　or　hollow　structures.　Both　the　rational　design　of　nano-MOFs　with　sophisticated　structures　and　the　comprehensive　knowledge　of　their　formation　mechanism　remain　an　interesting　research　topic.　In　this　work,　we　reported　a　highly　peculiar　zigzag　crystal　of　a　Prussian　blue　analogue　(PBA)　bearing　the　ensemble　of　walls　with　uniform　thickness　(∼60　nm)　in　three-dimensional　space.　Such　＇Z＇-like　PBA　was　acquired　by　the　preferential　etching　of　two　opposing　corners　of　its　parent　NiCo-PBA　cubes　that　was　pre-doped　by　metal　ligand　ions　(i.e.,　[Fe(CN)6]3−).　Mechanistic　studies　suggested　that　the　anisotropic　etching　seemed　to　arise　from　the　heterogeneous　growth　and　inhomogeneous　spatial　distribution　of　the　FeIII　and　FeII　(stemming　from　redox　reaction　of　FeIII)　species,　even　though　all　the　metal　elements　(including　Fe,　Co,　and　Ni)　were　evenly　dispersed　in　each　individual　cube　as　indicated　by　HAADF-STEM　and　linear　EDS　scan　analyses.　The　open　＇Z＇　structure　provided　larger　surface　area　and　a　greater　number　of　active　sites　to　activate　reagents　in　catalytic　reaction　and　enhanced　the　degradation　efficiency　in　removing　bisphenol　A　from　aqueous　solution　with　PMS.　The　current　findings　are　expected　to　pave　way　for　a　fine　tuning　the　structures　and　properties　of　MOFs,　and　encourage　extended　research　on　developing　novel　anisotropic　crystals.　©　2019　Elsevier　B.V.