<p>Double perovskites are currently materials of attention for renewable energy sources because of their intriguing characteristics, which include their stable yet simple crystal structure. The structure, electrical, optical, mechanical, elastic, thermodynamic, and thermoelectric characteristics of A₂ScCuCl₆ (A = Li, Na) double perovskites are examined in the current work utilizing density-functional theory (DFT). The compounds are stable in the cubic phase. The elastic parameters have confirmed both materials' mechanical stability, flexibility, and anisotropic behavior. The estimated band gaps for A₂ScCuCl₆ (A = Li, Na) are 1.83 and 1.80 eV, respectively which lie in the visible region of the electromagnetic spectrum. The light-matter interaction is reported in terms of dielectric function based optical parameters. Their bandgap is consistent with their low reflectivities, which makes them highly absorbing to incoming photons. JARVIS (Joint Automated Repository for Various Integrated Simulations) was utilized to compute the SLME (%) versus thickness (µm). The transport parameters were also evaluated by employing the Seebeck coefficient (S), electrical conductivity (σ), thermal conductivity, and figure of merit (ZT). Hopefully, our findings will be beneficial in appraising A₂ScCuCl₆ (A = Li, Na) in the next studies for usage in renewable energy devices.</p>