Cu₂O/HKUST-1 core/sheath nanostructures and hierarchical HKUST-1 nanotubes were fabricated by direct conversion of Cu₂O nanowires in ethanol/N,N-dimethylacetamide (4 : 1 of v/v) mixed solution of benzene-1,3,5-tricarboxylic acid and dissolving the core with 0.175 M acetic acid consecutively. The resulting nanotubes showed an improved and fast uptake of methylene blue and congo red.