Nanomaterials as zinc oxide have potential applications in nanomedicine, biosensors, catalysts, and biomedical bio-imaging because of their intrinsic optical properties. We report the synthesis and characterization of zinc oxide nanostructures in the presence of ethylene glycol and the effect of the zinc precursor on the intensity of the photoluminescence. Zinc oxide nanoparticles were generated in the presence of ethylene glycol as solvent and zinc precursors at 197 °C using a reflux system. The reaction time was ranged from 2–6 h, and the precursors evaluated were zinc (II) sulfate heptahydrate and zinc (II) acetate dehydrated. As-synthesized nanostructures were characterized by absorption and photoluminescence spectroscopies. Results evidenced that nanostructures exhibited emission peaks at 326 nm and trap peaks between 389 and 401 nm. At the same time, the absorption spectra showed shoulder peaks at approximately 360–364 nm, which is attributed to the exciton. The photocatalytic capacity of synthesized nanomaterials was evaluated using a spectrophotometric method. The effect of the catalyst dose and exposure time were investigated. Results demonstrated that, the maximum degradation of Amaranth and Tropaeolin O was 74% and 81%, respectively, after contact with concentrations of 500 ppm of light-activated ZnO.