Due to their rich and extraordinary properties, halide perovskites have gained attention over time for their applications in thermoelectric and solar cells. Here, several physical properties (stability, photovoltaic, and thermoelectric) of inorganic halide perovskites XZnI₃ (X = Na, K, Rb, Cs) are predicted using the density functional theory (DFT) within the Wien2k code. The optimization of structural parameters has been calculated using PBE-GGA approach. The tolerance factor, Born criteria, phonon dispersion, and negative formation energy show the formation and stability of these studied materials in the ideal cubic structure. Additionally, the modified Becke-Johnson method is applied for optoelectronic and transport properties. All compounds exhibit the nature of indirect band gap semiconductors with better absorption in the visible and ultraviolet regions . The transport properties present high electrical conductivity, large Seebeck coefficient, and good (PF, ZT) factors for all these materials. Finally, all these properties of inorganic halide perovskites open up new possibilities for efficient applications in thermoelectric and solar cells.