Hexagonal boron nitride (hBN) is an indirect bandgap semiconductor with a wide bandgap, high thermal and chemical stability, and unique electronic properties. This study resolves the long-standing debate about the bandgap nature of hBN by demonstrating an indirect bandgap of 5.955 eV through optical spectroscopy. The research shows that phonon-assisted optical transitions play a crucial role in hBN's optical properties, and that exciton binding energy is approximately 130 meV, indicating Wannier-type excitons. The study also identifies various phonon modes in hBN's emission spectrum and confirms the indirect nature of the bandgap through two-photon spectroscopy. The results show that hBN's single-particle bandgap is about 6.08 eV. The findings highlight the importance of theoretical calculations in understanding hBN's exciton-phonon interactions and suggest future experiments to explore hBN's properties in both 3D and 2D forms. The study provides a comprehensive understanding of hBN's opto-electronic properties in the deep ultraviolet, confirming its potential as a material for advanced optoelectronic applications.Hexagonal boron nitride (hBN) is an indirect bandgap semiconductor with a wide bandgap, high thermal and chemical stability, and unique electronic properties. This study resolves the long-standing debate about the bandgap nature of hBN by demonstrating an indirect bandgap of 5.955 eV through optical spectroscopy. The research shows that phonon-assisted optical transitions play a crucial role in hBN's optical properties, and that exciton binding energy is approximately 130 meV, indicating Wannier-type excitons. The study also identifies various phonon modes in hBN's emission spectrum and confirms the indirect nature of the bandgap through two-photon spectroscopy. The results show that hBN's single-particle bandgap is about 6.08 eV. The findings highlight the importance of theoretical calculations in understanding hBN's exciton-phonon interactions and suggest future experiments to explore hBN's properties in both 3D and 2D forms. The study provides a comprehensive understanding of hBN's opto-electronic properties in the deep ultraviolet, confirming its potential as a material for advanced optoelectronic applications.