Co_3−xCu_xO₄ nanorods with a crystalline structure were synthesized via a solution process in this study. The Co_3−xCu_xO₄ nanorods exhibit dual direct bandgaps and could be adjusted to 1.3–1.5 eV, and 2.55–3.5 eV by using different Cu-doping concentrations. The Co_3−xCu_xO₄ nanorods show an absorption coefficient of ∼10⁴ cm⁻¹ which increases with the increase of the Cu doping concentration.