There has been evidence of non-typical fluorescence activities in thiadiazole and oxadiazole derivatives. Also,
some coumarin compounds with tunable luminescence properties via controlling the molecular structure and its
aggregation have been recently reported. As a result, our effort concentrated on integrating these moieties in
order to improve the applicability of the target compounds through easy synthetic schemes. All the synthesized
derivatives underwent extensive spectrum analysis, including NMR, FT-IR, and mass spectroscopy. DFT calculations,
UV–visible, and luminescence spectroscopy were used to study the photophysical characteristics of three
compounds having coumarin luminescent core integrated with the thiadiazole, oxadiazole, or hydrazinecarbothioamide.
We found that manipulating the packing of a compound under specific conditions (e.g., the solid state
or moderate solution concentration of compounds containing the heterocyclic substituent “thiadiazole or oxadiazole”)
can trigger processes related to the way the molecules interact, resulting in the appearance of dual or
multiple fluorescence bands that cover the full visible range. Additionally, we deduced that the intriguing white
emission from a single component might be generated by modifying the degree of molecular aggregation to
balance the relative band intensities at short and long wavelengths. Long-wavelength emission arises from
aggregated molecules whereas short-wavelength emission results from single molecules. It is evident that this
balance is feasible in both the solid form of the thiadiazole derivative and 1 × 10–5 mol L–1 solution of the
oxadiazole derivative. Hence, this research proposes an easy method for creating the intriguing white-light
emission from a single component.