Wurtzite polymorph of boron nitride (wBN) was first obtained in the 1960s starting from hexagonal boron Nitride (hBN) under high pressure. Since then, several studies have been conducted on samples obtained mostly by use of the shock compression technique which allowed the production of micrometer BN powder of both wurtzite and cubic phases. Moreover, wBN has long been recognized as a metastable material since it tends to undergo a transition back to the hexagonal phase. Recently, it has been shown that it is possible to produce larger and purer samples of wBN and that they can be stabilised by macroscopic defects in the crystals. Since this material is a wide-band-gap semiconductor believed to have a hardness comparable to that of cubic boron nitride (cBN) and diamond, its implementation in optoelectronic devices in harsh environments can be envisaged. We characterized the electronic properties of wBN by use of the quasi-particle formalism in G 0 W 0 approximation on top of Density Functional Theory in Generalized Gradient Approximation (DFT+GGA) in order to take into account screening effects usually neglected in standard DFT calculations. Optical properties were studied by mean of the Bethe-Salpeter equa-
tion (BSE). Finally, we studied the Boron vacancy in wBN since its wide band gap makes it a good candidate to host defect levels that can find applications in quantum technologies.