We review the discovery of a new phase BN (named Q-BN) which has been created by nanosecond laser melting in the super undercooled state and quenching rapidly with rates exceeding several billion degrees per second. This phase, sequel to our earlier discovery of Q-Carbon, has amorphous structure from which phase-pure c-BN is formed in the form of nanodots, microcrystals, nanoneedles, and microneedles. Large-area single c-BN are formed by providing a template for epitaxial growth during quenching of super undercooled liquid BN. Since there is a rapid crystal growth from liquid, both n- and p-type dopants can be incorporated into electrically active substitutional sites with concentrations exceeding solubility limits through the phenomenon of solute trapping. We have grown diamond on c-BN by pulsed laser deposition of carbon at 500°C without the presence of hydrogen, and created c-BN and diamond epitaxial composites. We discuss the mechanism of epitaxial c-BN and diamond growth on lattice matching c-BN template under pulsed laser evaporation of amorphous carbon. This discovery on direct conversion of h-BN into phase-pure c-BN at ambient temperatures and pressures in air, represents a seminal contribution to the field of boron nitride, which is quite complementary to our discovery of graphite to diamond conversion. We have bypassed thermodynamics with the help of kinetics and time control. This research represents a major breakthrough for c-BN and diamond based high-power electronic and photonic devices, and host of other applications related to high-speed machining, deep-sea drilling, field-emission displays and biomedical applications.