Fabrication　of　low-dimensional　nano-MOFs　as　well　as　nanoparticles/metal-organic　frameworks　(MOFs)　hybrids　has　sparked　new　scientific　interests　but　remains　a　challenging　task.　Taking　Cu　3　(BTC)　2　as　a　proof　of　concept,　it　is　demonstrated　thats　NH　3　⋅H　2　O　solution　of　a　confined　pH　value　can　readily　shape　the　bulk　Cu　3　(BTC)　2　into　nanoscale　Cu　3　(BTC)　2　,　beyond　the　need　to　control　the　crystal　growth　kinetics　of　MOFs.　Adjusting　the　pH　of　NH　3　⋅H　2　O　within　a　much　small　range　(10–11)　allows　fine　tuning　over　the　size　and　shape　of　nanoscale　Cu　3　(BTC)　2　.　Particularly　at　pH　=　11,　NH　3　⋅H　2　O　exhibits　weak　reducibility　that　triggers　a　reduction　of　part　of　Cu　3　(BTC)　2　into　Cu　2　O,　while　shaping　the　other　into　Cu　3　(BTC)　2　nanowires.　Benefiting　from　the　coincidence　of　reduction　and　etching　effects,　the　newly　generated　Cu　2　O　dots　can　in　situ　anchor　onto　adjacent　Cu　3　(BTC)　2　nanowires　at　highly　dispersive　state,　forming　a　well-defined　sponge-like　architecture　built　of　Cu　2　O　dots　and　nano-Cu　3　(BTC)　2　.　The　CuO　x　derived　from　annealing　of　the　Cu　2　O　dots/nano-Cu　3　(BTC)　2　hybrid　preserves　the　sophisticated　sponge　architecture　and　high　porosity,　and　exhibits　promising　applications　in　phenol　scavenging,　with　efficiency　outperforming　its　counterparts　and　many　other　Cu-based　catalysts　reported　in　literature.　It　is　anticipated　that　the　findings　here　pave　the　way　for　the　rational　design　of　intricate　nano-MOFs　in　a　more　efficient　way.　©　2019　WILEY-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim