Tetrazoles, with their unique properties, are prominent candidates for advanced energetic materials in materials science. Understanding their physical and chemical characteristics is crucial for enhancing performance and innovating new tetrazole-based compounds. In this study, we utilize first-principles calculations to investigate the properties of nitrogen-enriched 5-Aminotetrazolium Nitrate (5-ATN), aiming to advance its application as an energetic material. Our extensive analysis includes the structural, mechanical, vibrational, optical, and electronic properties of 5-ATN. Theoretical results, especially with van der Waals (vdW) corrections, align well with experimental data. Elastic constants confirm mechanical stability and reveal differential shock sensitivities, particularly along the b-axis. Infrared spectral analysis identifies unique fingerprint peaks, crucial for detection. The electronic structure, determined using the Tran-Blaha modified Becke-Johnson (TB-mBJ) potential, yields an energy band gap of approximately 4.5 eV, overcoming the underestimation issues of traditional LDA and GGA methods. Optical constant variations indicate anisotropy and suggest potential photodecomposition in the ultraviolet (UV) spectrum. This investigation provides critical insights to guide the design and optimization of tetrazole-based energetic materials, enhancing their efficiency, stability, and performance in high-energy applications.