CDK12-IN-3 is primarily used in research settings to study the role of CDK12 in cellular processes, particularly in cancer biology. It acts as a selective inhibitor of CDK12, a cyclin-dependent kinase involved in transcription regulation and DNA damage response. Researchers utilize this compound to investigate its potential in disrupting cancer cell proliferation, especially in cancers where CDK12 is overexpressed or dysregulated. Its application extends to understanding the mechanisms of transcription elongation and DNA repair pathways, which are critical in developing targeted cancer therapies. Additionally, CDK12-IN-3 is explored for its synergistic effects when combined with other anticancer agents, offering insights into combination treatment strategies.