This chapter provides a brief overview of the recent development of hexagonal boron nitride (h-BN) quasi-bulk crystals as an ultrawide bandgap (UWBG) electronic material. Hydride vapor phase epitaxy (HVPE) growth was employed to obtain h-BN quasi-bulk wafers up to 4 inches in diameter and 100 μm in thickness. Benchmarking against the state-of-the-art mm-sized bulk crystals and thin epitaxial films produced by metal organic chemical vapor deposition (MOCVD) revealed that these quasi-bulk wafers have a good stacking sequence and long-range order in the direction parallel to the c-axis. Electrical transport characterization results revealed that these materials possess an electrical resistivity of ρ > 1 × 1013 Ω⋅cm and a charge carrier mobility and lifetime product of μτ=2 × 10−4 cm2/V. Detection of thermal and fast neutrons has also been demonstrated with a record high thermal neutron detection efficiency of 60%. Experimental results of doped and unintentional doped impurities, including C, Si, Mg, and O are discussed. Characterization results of optical and transport properties revealed that reducing the density of native defects remains the most critical task for h-BN quasi-bulk crystal growth by HVPE. These recent developments serve as a solid stepstone for advancing the crystal growth technology to produce electronic grade h-BN quasi-bulk crystals.