• Cs2B(IV)X6 double perovskites are promising eco-friendly alternatives to lead-based perovskites for optoelectronics.
• Recent advances in ion doping, surface coating, and ligand modification have significantly improved their photoluminescence properties.
• The review highlights strategies for bandgap engineering and PL optimization to enhance device performance.
• Key challenges remain in improving photoluminescence quantum yield and stability, guiding future research directions.