Hematite (α-Fe2O3) and Ni doped Hematite (α-Fe2O3) nanoparticles were synthesized with different pH values employ with catharanthus roseus leaf extract as reducing and capping agents. X-ray diffraction analysis reported that the prepared nanoparticles exhibited rhombohedral in structure. FESEM micrographs revealed the prepared nanoparticles are needle in structure to plates like structure when the pH value is increased. FTIR analysis confirmed the bonds and functional groups of the prepared Hematite (α-Fe2O3) and Nickel doped Hematite (α-Fe2O3) nanoparticles. The UV spectra of the prepared nanoparticles revealed the band gap energies ranging from 1.12 eV to 1.54 eV. The hysteresis loop showed the magnetic properties of the prepared nanoparticles exhibited ferromagnetic behavior. The antioxidant DPPH radical scavenging and the antimicrobial activity confirmed the inhibition of nanoparticles against gram positive and gram negative bacteria in concentration dependent manner. Moreover, the cytotoxicity effect against MCF-7 cancer cell lines revealed the inhibitory potential of the prepared nanoparticles. Bio efficacy of the prepared nanoparticles may leads to its potential and practicable applications in environmental and biomedical fields.