The research examines the exceptional physical characteristics of Mg3AB3 (A = N, Bi; B = F, Br, I) perovskite compounds through density functional theory to assess their feasibility for photovoltaic applications. Mechanical characterization further supports their stability where out of all the compounds, Mg3BiI3 demonstrates high ductility, while Mg3NF3 and Mg3BiBr3 possess a brittle nature. The calculated elastic constants and anisotropy factors also substantiate their mechanical stability, while there is an observed declining trend in Debye temperature with increase in atomic number. From the electronic point of view, Mg3NF3 can be considered as a wide-bandgap insulator with the bandgap of 6.789 eV, whereas Mg3BiBr3 and Mg3BiI3 can be classified as semiconductors suitable for photovoltaic applications bandgaps of 1.626 eV and 0.867 eV, respectively. The optical characteristics of such materials are excellent and pronounced by high absorption coefficients, low reflectivity, and good dielectrics, which are very important in the collection of solar energy. Among them, Mg3BiBr3 and Mg3BiI3 possess high light absorption coefficient, moderate reflectivity, and good electrical conductivity, indicating that they are quite suitable for applying the photoelectric conversion materials for solar cells. In addition, thermal analysis shows that Mg3NF3 is a good heat sink material, Mg3BiBr3 and Mg3BiI3 are favorable for thermal barrier coating materials. Due to their high absorption coefficients, low reflectance and suitable conductivity, both Mg3BiBr3 and Mg3BiI3 could be regarded as the most appropriate materials for the creation of the next generation of photovoltaic converters.