Innovative, sustainable therapies are urgently needed for neglected vector-borne parasitic diseases. In this study, we leveraged cashew nutshell liquid (CNSL), an agro-industrial byproduct, to develop biobased phosphonium and ammonium salts (5-25) targeting parasite mitochondria. By combining CNSL-derived C8 alkyl chains with lipophilic cations, we synthesized novel compounds exhibiting highly potent in vitro and ex vivo activity against Trypanosoma and Leishmania spp., including veterinary-relevant strains like T. b. evansi and T. b. equiperdum. Compounds 5 and 7 outperformed reference drugs, demonstrating subnanomolar efficacy against Trypanosoma brucei spp., high selectivity indices (>1000), and no cross-resistance with current therapies, underscoring their potential as next-generation antitrypanosomal agents. Reduced activity against T. brucei overexpressing alternative oxidase and against Trypanosoma congolense supports a mitochondrial mechanism. Preliminary bioassays in zebrafish and Daphnia magna indicated ecotoxicity lower than antiparasitic activity. These CNSL-derived agents represent promising, environmentally safer antiparasitic candidates aligned with One Health and Green Chemistry principles.