Quinoline is an organic compound with a bicyclic structure, consisting of a benzene ring fused to a pyridine ring. It is a colorless to yellowish liquid with a distinctive odor and is primarily used in the production of dyes, pharmaceuticals, and agrochemicals. Quinoline can be derived from coal tar or synthesized through various chemical reactions. This compound is notable for its role in the development of several important drugs, including chloroquine, which is used to treat malaria. Quinoline derivatives are also studied for their potential applications in materials science and as fluorescent probes in biological research.