CDK9-IN-1 is primarily used in research settings to study the role of cyclin-dependent kinase 9 (CDK9) in various cellular processes. It is a potent and selective inhibitor of CDK9, making it a valuable tool for investigating the regulation of transcription, particularly in the context of cancer and viral infections. Researchers use CDK9-IN-1 to explore its effects on RNA polymerase II-dependent transcription elongation, which is crucial for the expression of genes involved in cell growth and survival. Additionally, it is employed in studies aimed at understanding the mechanisms of CDK9 in diseases such as HIV, where CDK9 plays a role in viral replication. By inhibiting CDK9, this compound helps in elucidating potential therapeutic strategies for targeting CDK9-dependent pathways in cancer and viral diseases.