Spectral investigations of the new organic semiconductor of the formula (TMTSF)2[3,3′-Co(1,2-C2B9H11)2], were performed using Raman and quantum chemical simulation methods. The polarized Raman spectra of single crystals of the salt were recorded in the range 150–3100 cm−1. An assignment of the strongest vibrational Raman lines was proposed. The possibility of the presence of two rotamers of the Co anion has been discussed taking into account the DFT calculations and the experimental spectra of the reference material.