<p>Owing to the interesting physical characteristics of perovskites, herein, we investigate RbZnX₃ (X = Cl, Br) halide perovskites for sustainable green energy applications. All the given structures were made relaxed and minimum energy was attained by employing Birch-Muranghan equation of state. The electronic band structure of the under study materials were calculated through modified-Beck-Johnson potential. Our results showed that all the investigated RbZnX₃ (X = Cl, Br) perovskites are semiconductors with band gaps of 1.34, and 0.12&#xa0;eV, respectively. The calculated tolerance factors, formation energies, Born-Hung criteria, phonon spectra and ab initio molecular dynamic (AIMD) simulations demonstrated that the given compounds exhibit geometrical, thermodynamic, mechanical, dynamic and thermal stabilities. Findings of elastic investigation revealed an elastic, anisotropic, and ductile nature of our predicted compounds. Moreover, all the studied materials revealed strong absorption – 10⁴&#xa0;cm⁻¹ in the visible and ultraviolet spectrum and the device absorption efficiency (%) was found comparable to other known reported materials. Overall, this study demonstrates that our simulated perovskites are suitable candidates for photovoltaic and optoelectronic applications.</p>