The present study focuses on synthesizing Cu-bismuth oxide (CuBi2O4) based nanorods by using a simple co-precipitation method for the photocatalytic degradation of caffeic acid (CA). Incorporating Cu metal ions during the synthesis of CuBi2O4 nanorods might be advantageous to avoid aggregation and control the leach out of metal ions. The calculated bandgap values of ~ 1.04, 1.02, and 0.94 eV were observed for CuBi2O4 with different amounts of Cu 1.0, 0.50, and 0.25 g, respectively. Varying quantities of Cu metal ions easily tuned the bandgap value within the CuBi2O4 based nanorods. However, a further decrease in the bandgap value increased the recombination rate; less photocatalyst performance was observed. The Cu within the CuBi2O4 based nanorods changed the electronic properties as well as the antibacterial ability. Therefore, the synthesized CuBi2O4 based nanorods cluster might be a promising material for the photocatalytic degradation of CA.