Bipolarithizole A (1), an unprecedented phenylthiazole-sativene sesquiterpenoid hybrid, has been isolated from cultures of the potato endophytic fungus Bipolaris eleusines. The structure with absolute configuration has been established by spectroscopic analysis and quantum chemical computational approaches, as well as by X-ray diffraction analysis. The plausible biosynthetic pathway for 1 has been proposed. Compound 1 shows anti-pathogenic fungi activity against Rhizoctonia solani with an MIC value of 16 μg mL⁻¹.