Photocatalysis offers a sustainable approach to degrade toxic organic pollutants from wastewater. Zinc oxide (ZnO) thin

films exhibit strong potential for high-performance photocatalytic applications; however, their wide band gap and rapid

electron–hole recombination significantly limit their efficiency. This limitation can be mitigated by incorporating metal

dopants during the photolysis decomposition process, which effectively narrows the band gap and suppresses charge carrier

recombination, thereby enhancing the overall photocatalytic activity. Here, we report the fabrication of copper (Cu)

and manganese (Mn) co-doped ZnO layers through a facile and efficient spin-coating method, to enhance the catalytic

efficiency of synthetic pigments. The doping atoms (Cu + Mn) were successfully incorporated into ZnO thin films without

destroying the ZnO crystal structures. The incorporation of dopant atoms into ZnO thin films reduced the band gap and

introduced intermediate energy levels, facilitating efficient charge separation and suppressing electron–hole recombination.

Under visible light irradiation, the (1% Cu + 8% Mn)-doped ZnO thin film exhibited superior photocatalytic activity,

attributed to the strong surface plasmon resonance of the dopant atoms and the improved charge carrier transport within

the film’s nanostructures. Photocatalytic degradation tests performed on organic dyes, including methyl orange, malachite

green, methylene blue and congo red demonstrated degradation efficiencies exceeding 94% within 120 min. This study

offers an eco-friendly and innovative viewpoint for developing visible-light-responsive (Cu, Mn): ZnO-based photocatalysts,

which are projected to be utilized for the remediation of environmental contaminants and can be reused multiple

times without a degradation in efficiency.