Abstract
In the last century, the impact of fluorescent technologies has been very prominent and omnipresent in improving the quality of life of humans, especially in medical applications such as molecular probes, cellular imaging and medical diagnostics. However, most fluorescent compounds are severely hindered by difficult and challenging synthetic methods, adulterants of impurities, and complex molecular structures, which limit the deep understanding of their structure-property relationships. In this thesis, under the overarching theme of design-based methodologies, we present indepth investigations on the structural-property relationships for two types of isomers (constitutional isomers and conformers) via the combination between experimental observations and theoretical calculations. A generalizable design strategy will be outlined that demonstrates how to induce highly desirable dye molecules with long peak absorption wavelengths and enhanced maximum molar absorption coefficients, based on constitutional isomerization. We also proposed a simple but novel way to construct highly sensitive and reliable ratiometric thermometers based on commercially-available fluorophores with multiple stable conformational isomers at different temperatures. We hope that the studies presented herein, will inspire and encourage other dye chemists in the field to recognize the importance of and to further explore the structure-property relationships of fluorophores.