Structure-activity relationships (SARs) are keys to the success of drug discovery and development programs as they provide the pivotal link between structural modifications and desirable biological activities. To this end, viable synthetic strategies must be robust and accommodate a wide range of functional group installations at various stages to generate libraries of candidates with sufficiently explored chemical spaces. Detailed molecular mechanisms of biological actions have been performed to shed some light on understanding the interactions between the molecular target and ligands. Similar to modern drug discovery programs, toxicological profiling has been integrated at an early stage to enhance the success rate of advancing these drug-like candidates to further stages of drug discovery and development process.