The optical properties of the pristine materials and nanocomposites were analyzed using UV-Vis absorption and PL spectroscopy. The absorption spectrum of ZIF-8 (Figure ), measured in methanol, shows a distinct maximum at 210 nm. Due to the poor stability of CPB NCs and CPB/ZIF-8 nanocomposites in polar solvents, hexane was used as the dispersion medium for these measurements. However, as hexane is UV-active, absorption below 300 nm could not be recorded. The pristine CPB NCs and CPB/ZIF-8 exhibit absorption edges at 512 nm and 511 nm, respectively (Figure ). The negligible shift in the absorption edge between pristine CPB and the nanocomposite confirms that the optical activity of the CPB NCs remains intact within the CPB/ZIF-8.