NSC-323241 is a potent inhibitor of STT3A-mediated mega protein complex assembly. It disrupts the large endoplasmic reticulum (ER) complexes localized by STT3A during dengue virus (DENV) and Zika virus (ZIKV) infections. NSC-323241 interferes with the binding of the STT3A subcomplex to viral non-structural proteins (such as NS2B, NS3) and host transporter proteins, thus impairing the formation of the viral replication microenvironment. This compound holds promise for researching flavivirus infections, including dengue and Zika viruses.