Changes to the electronic structures and properties of semiconductor oxides depend on the individual properties of dopants used. Aliovalent dopants are an integral part of this doping strategy to modify the electronic, chemical and optical properties of Ti(IV)–based oxides. The grand challenge in quantum information processing is the precise manipulation of quantum spins, both individually and collectively. This capability is essential for the development of reliable quantum computers and advanced quantum communication systems. Aliovalent magnetic dopants like transition metals when doped into the Ti(IV)–based oxides render them useful for spintronics, photocatalysis, and optoelectronics. The use of dopant specific spectroscopic techniques such as electron paramagnetic resonance (EPR) spectroscopy plays a vital role in determining both the transition metal dopant oxidation state and dopant position in the colloidal nanocrystals (NCs). Using EPR spectroscopy the dopants and defects were unambiguously identified and characterized. Photochemical introduction of excess carrier densities is achieved under anaerobic conditions with a sacrificial reductant ethanol being present. Studies were carried out to understand the effect of host lattice crystal structure and site symmetry for the Manganese (Mn) dopants in SrTiO3, BaTiO3 and TiO2. The spectroscopic studies on the effect, the presence of these excess charge carriers in the form of Ti3+ “self-trapped” defects have on spin dynamics for Mn-doped Ti (IV)–based oxides was carried out. We were able to develop and study a class of materials that possess substantial magnetic dopants, and tunable charge carrier densities in the form of defects. This valuable ability to refine and control the magnetic properties by simply using photons contributes to the fundamental understanding of carriers' interactions in oxide semiconductors and provides insights into the pathways for charge and spin-based applications for energy storage and quantum information processing.