Quantum point defects in solid state hosts are one of the most promising tools in quantum technology applications. Their excellent optical and spin properties combined with their nanoscale size make them especially successful in sensing applications. Furthermore, they show great promises in quantum communication for long distances and in the creation of quantum networks. Some of the challenges in these applications and the proposed solutions will be discussed in this report. Applying advanced density functional theory, the key magneto-optical properties and their coupling to external perturbations are calculated for various quantum defects in order to describe their capabilities and limitations.