Bromoiesol sulfates A (1) and B (2), new polyhalogenated aryl sulfates, were isolated from a Salileptolyngbya sp. marine cyanobacterium along with their hydrolyzed compounds, bromoiesols A (3) and B (4). To pick up the candidates of their structures, we used Small Molecule Accurate Recognition Technology (SMART), an artificial intelligence-based structure-prediction tool, and their structures were elucidated on the basis of single-crystal X-ray diffraction analysis of bromoiesols (3 and 4). In addition, to verify the structures, the total synthesis of bromoiesol A sulfate (1) and bromoiesol A (3) was achieved. The bromoiesol family, especially bromoiesols (3 and 4), selectively inhibited the growth of the bloodstream form of Trypanosoma brucei rhodesiense, the causative agent of human African sleeping sickness.