YM-26734 is primarily utilized in research settings for its potential as a selective antagonist of the 5-HT2B receptor. This property makes it a valuable tool for studying serotonin receptor signaling pathways and their roles in various physiological processes. Researchers often employ it to investigate the involvement of 5-HT2B receptors in conditions such as cardiovascular diseases, pulmonary hypertension, and fibrosis. Additionally, its selective action helps in distinguishing the effects of 5-HT2B receptors from other serotonin receptor subtypes, aiding in the development of targeted therapeutic strategies. Its application is largely confined to preclinical studies, where it contributes to a deeper understanding of receptor mechanisms and drug discovery efforts.