Two types of cupric oxide (Cu₂O) nanoarchitectures (nanobelts and nanopetal networks) have been achieved via immersion nanoporous copper (NPC) templates in anhydrous ethanol. NPC templates with different defect densities have been prepared by dealloying amorphous Ti₆₀Cu₄₀ ribbons in a mixture solution of hydrofluoric acid and polyvinylpyrrolidone (PVP) with different ratios of HF/PVP. Both a water molecule reactant acting as OH⁻ reservoir and the ethanol molecule serving as stabilizing or capping reagent for inhibiting the random growth of Cu₂Oplayed a role of the formation of 2-dimensional Cu₂O nanoarchitectures. Cu₂O nanobelts are preferred to form in anhydrous ethanol on the NPC templates from Ti₆₀Cu₄₀ ribbons dealloying in the solution with low HF concentration and small addition of PVP; and Cu₂O nanopetals are tended to grow in anhydrous ethanol from the NPC templates from Ti₆₀Cu₄₀ ribbons dealloying in the solution with high HF concentration and large addition of PVP. With increasing the immersion time in anhydrous ethanol, Cu₂O nanopetals united together to create porous networks about 300 nm in thickness. The defect sites (i.e., twin boundary) on nanoporous Cu ligaments preferentially served as nucleation sites for Cu₂O nanocrystals, and the higher defect density leads to the formation of uniform Cu₂O layer. Synergistic effect of initial microstructure of NPC templates and stabilizing agent of ethanol molecule results in different Cu₂O nanoarchitectures.