Green synthesized nanoparticles have gained momentum compared to their counterparts in various applications. In this study, Se@Ag/AgO, Se@ZnO and Se@Ag/AgO-ZnO nanocomposites were produced by green synthesis method using Pinus nigra pollen extract as a reducing agent. The structural, optical and morphological properties of Se-doped nanoparticles and nanocomposites were examined using FT-IR, XRD, UV-Vis, SEM, and EDS. The photocatalytic properties were investigated against methylene blue dye and tetracycline which is a widely used antibiotic. It was observed that selenium doping in Ag/AgO-ZnO nanocomposite has enhanced the photodegradation of tetracycline antibiotic. While Se-doped Ag/AgO and Se-doped ZnO nanocomposites showed high rates of photocatalytic activity against methylene blue dye, Se-doped Ag/AgO-ZnO exhibited the best degradation rate against tetracycline. Furthermore, the antibacterial properties of these nanocomposites produced by green synthesis were tested against S. aureus, P. aeruginosa and E. coli. The results revealed that Se-doped ZnO showed higher inhibition zone against S. aureus and E. coli, while Se-doped Ag/AgO showed the highest inhibition zone against P. aeruginosa. The broth micro dilution test confirmed the data obtained from disc diffusion assay. The strains were massively affected from Se-doped Ag/AgO at a MIC of 0.014 mg/mL.