We report the novel chalcone–benzoxaborole hybrids and their structure–activity relationship against Trypanosoma brucei parasites. The 4-NH2 derivative 29 and 3-OMe derivative 43 were found to have excellent potency. The synergistic 4-NH2-3-OMe compound 49 showed an IC50 of 0.010 μg/mL and resulted in 100% survival and zero parasitemia in a murine infection model, which represents one of the most potent ...