In this contribution we report initial results of our solid phase vibrational spectroscopic study of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) and derivatives representing its protonation and oxidation states, We have succeeded in assigning observed bands to modes which are diagnostically useful for studies concerning the electrochemical character of DMcT when used with polyaniline (PAn) as a composite cathode material in a secondary lithium-ion cell. We discuss the implications of the current study for our further investigations of the DMcT/PAn cathode.