Pristine CsPbBr3 and Cs4PbBr6 NCs were dispersed in Sol.1 to a total volume of 20 mL and a final concentration of 52 µM. Then, 10 mL of MO solution was added to the dispersed NCs and kept under constant stirring. The samples were placed 15 cm from the Xenon lamp source with a power of 60 mW/cm 2 and appropriate cutoff filters to utilize the visible light excitation. For CsPbBr3 NCs, the degradation was analyzed with 5-min time intervals. Every 5 min, 2.5 mL of solution was taken and centrifuged at 7000 rpm for 3 min. The supernatant was subjected to absorption measurement to study the photocatalytic dye degradation. Similarly, in the case of Cs4PbBr6 NCs, the degradation was performed at 30 min time intervals.