Magnetic Ferrite nanoparticles (MFNPs), are promising for diverse application owing to their divergent functional properties. Among the MFNPs cobalt ferrite nanocomposites have gained a lot of attention for myriad biomedical application. This paper describes our synthesis of nickel doped cobalt ferrite capped in polyethylene glycol (PEG), polyvinyl alcohol (PVA) and polyvinyl pyrolidone (PVP) by a hydrothermal method. Several characterizations techniques, such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM) were used to determine the physico-chemical properties of the formulated MFNPs. The physico-chemical properties of the MFNPs were influenced by the PEG, PVA and PVP. The formulated nanoparticles showed enhanced antidiabetic, antioxidant and antimicrobial activities. The PVP capped MFNPs, had the highest antifungi and antidiabetic activities, while the PVA capped MFNPs showed the highest antibacterial and antioxidant activities. Hence, the introduction of these polymers in the samples heightened their biomedical performance. The photodegradation of crystal violet by the MFNPs was also enhanced with the PVP mediated sample having the highest efficiency.