This study employed a green route to synthesize metal oxide nanocomposites, specifically NiO/Al2O3, which were subsequently used to dope poly(methyl methacrylate) (PMMA) as a matrix, resulting in the formation of novel nanocomposites, namely PMMA/NiO/Al2O3. The nanocomposites were characterized using FE-SEM, XRD, DSC, TGA, antioxidant activity, and antibacterial activity tests to confirm their design, verify the nanostructured composition, and distinguishable features in poly methyl methacrylate distribution. The results of AFM for the synthesized nanostructured showed that the NiO and Al2O3, describe how the nanoparticles' size was in the nano scale. The biological activities of nanocomposites synthesized were studied, including antioxidant and the use of these nanocomposites as inhibitors for bactria also as anticancer. The findings for all of these nanocomposites revealed they have the properties of a significant inhibitory effect.