Antiviral agent 36 (compound 27) is a potent dengue (DENV) and Zika (ZIKV) viruses inhibitor. Antiviral agent 36 inhibits replication of Zika and dengue virus with EC 50 s of 100 nM, 90 nM, 210 nM, and 120 nM for ZIKV-FLR, ZIKV-HN16, DENV-2, and DENV-3, respectively.