The Raman spectra of 4,5-C2B4H8, C2B4H7Me, and C2B4H6Me2 are presented, together with qualitative intensities and states of polarisation. Vibrational assignments are given for C2B4H8 using both Raman and remeasured i.r data and the results of published i.r. deuteriation studies, and comparative assignments are given for the methylated derivatives. The vibrational frequencies are partially correlated with the bonding in the polyhedral framework, and compared with data for the small closo-carboranes.