Two pairs of new enantiomeric benzofurans with unusual skeletons, (+)- and (−)-eupachinin A (1), as well as (+)- and (−)-eupachinin B (2), were isolated from the roots of Eupatoriumchinense by chiral HPLC. Their structures with absolute configurations were elucidated on the basis of spectroscopic methods, X-ray diffraction analysis, and quantum chemical calculation. The plausible biogenetic pathway