Used as an intermediate in the synthesis of fluorescent dyes and labeling agents, particularly in the development of probes for bioimaging and molecular detection. Its structure allows for easy functionalization, making it valuable in creating sensors for biological molecules. Also employed in research for developing novel kinase inhibitors and other pharmaceutical compounds due to the quinazoline core's affinity for enzyme active sites. Commonly utilized in conjugation chemistry for attaching reporter groups to antibodies or nucleic acids in diagnostic applications.