The variant perovskites are considered novel materials for studying solar cells and other electro-optic applica-tions. Born's stability criteria confirm the mechanical stability, while Poisson coefficient (nu > 0.26) and Pugh ratio (B0/G > 1.75) certify the ductile nature of the compounds by investigating elastic properties. For Cs2KGaI6 and Rb2KGaI6, the computed bandgap is direct 1.81 eV and 1.85 eV, respectively, in terms of exploring the band structures. Their band gaps may capture electromagnetic waves in the visible spectrum, excelling them for solar cell devices. The optical properties have been studied against photon energy (eV) with maximum transition and absorption in the visible region. BoltzTrap code is employed for the thermoelectric properties executed by electrical conductivity, thermal conductivity, power factor, and figure of merit (ZT), which shows a slight variation in the temperature. Hence, the considered lead-free double perovskite compounds offer applications in solar cell devices and p-type semiconducting behavior predictive in transport investigations.