This article presents a thorough density functional theory based comparative study on nitrogen-rich 5-aminotetrazole alkali metal salts M 5-At (M = Li, K, Rb, Cs). The calculated structural parameters using plane-wave pseudopotential method are consistent with the experimental results. The computed vibrational frequencies at ambient pressure show that vibrational modes in high energy region are due the N H bond of NH 2 group. Pressure variation IR spectra of these materials show clear frequency shifts where Li 5-At shows an overall red shift below 900 cm −1 contrary to the blue shift seen in other materials in this range. The born effective charge values reveal the presence of strong covalency between N, H, and C atoms whereas an increased ionic nature is seen as the atomic number of metal atoms increases. Furthermore, we used full potential linear augmented plane wave (FP-LAPW) method for calculating electronic structure and optical properties with TB-mBJ potential which provides an enhanced band gap for all materials compared to standard GGA functional. Electronic structure calculation reveals that all the compounds are indirect band gap insulators with the exception of Li 5-At. The computed partial density of states show mixed ionic-covalent nature in metal-N/C bonds and covalent nature in N C bonds. In addition, we are also presenting the optical properties such as real and imaginary dielectric constant, absorption, refraction, reflection, loss spectrum as functions of photon energy. From the optical properties we can conclude that all the studied compounds are optically anisotropic in nature and are good absorbers in the ultraviolet (UV) region. K E Y W O R D S 5-aminotetrazole, alkali metal salts, electronic properties, optical properties, vibrational properties 1 | INTRODUCTION Use of high nitrogen based energetic materials toward replacement of perchlorate in pyrotechnics is a subject of interest in recent times. Various derivative of perchlorate's are used since last few decades due to their intrinsic stability, low cost, reactivity, hygroscopic nature, and large positive oxygen balance. [1] Perchlorate based materials are now classified as environmentally dangerous and human health hazards. [2] These materials are believed to contaminate groundwater and interfere with the production and regulation of thyroid hormones, toxic and carcinogenic. [3,4] Research toward the replacement of rooted energetic materials (i.e., KClO 4 , NH 4 ClO 4 , Pb[N 3 ] 2) with increased performance and lower sensitivity to physical stimuli is hard to achieve. Over last few decades, rapid process in development of