The absolute configuration of polycephalin C (1) isolated from plasmodia of the slime mold Physarum polycephalum is supposed to be 300R,400R as found by comparison of CD spectra of the natural product polycephalin C (1) and CD spectra of synthetic bis-benzoates (2)- 4 and (þ)-4. An X-ray structure of the corresponding bis-camphanate (þ)-3 shows that the exciton chirality method may not be applied on these 1,4-diols in the usual manner.