Nickel Oxide having many technological applications was doped with Manganese. The ability of Mn to exist in many oxidation states when incorporated in lower concentration further enhanced the properties of NiO as observed through XRD, UV and PL studies. The generation of vacancies, excitons and lattice vibrations got altered effecting the band gap. Evidence of changes in particle shape was also found. The mechanism behind these phenomena which have technological importance in terms of photocatalysis and energy storage devices discussed.