The influence of temperature (in the range from 5°C to 65°C) on typical electrochemical reactions of diphenolic compounds spontaneously and irreversibly adsorbed in specific orientations at smooth polycrystalline electrodes has been investigated in 1 M perchloric acid electrolyte by means of thin-layer electrochemical methods. Six compounds were studied: hydroquinone (I), 1,4-naphthohydroquinone (II), 2,2′,5,5′-tetrahydroxybiphenyl (III), 2,5-dihydroxythiophenol (IV), 2,5-dihydroxy-4-methylbenzylmercaptan (V), and pentafluorothiophenol (VI). Three reactions were examined: reversible redox (quinone/diphenol couples); irreversible electro-oxidation; and reductive desulfurization (cleavage of the C-S bond). The thiophenol derivatives were adsorbed through the −SH moiety and showed complete reversible electroactivity at all temperatures; the voltammetric peak widths for adsorbed IV were noticeably large below 65°C. The fraction of reversibly electroactive adsorbed III (in the orientation in which only one ring is surface-attached) increased with temperature. The extent of irreversible electrochemical oxidation of I and II increased with temperature, regardless of orientation. The coulometric data indicated that CO 2 was the principal product from flat-adsorbed species above 5°C; for the edgewise orientation, the results suggested temperature-dependent product distribution, with CO 2 being the sole product at 65°C. The ease of reductive desulfurization of the thiophenol compounds was found to decrease in the order, VI>>IV>>V, which is opposite the trend observed for electro-oxidation (towards which the fluorinated derivative showed complete resistance). The efficiency of desulfurization for IV increased as the temperature was raised from 5°C to 25°C. At higher temperatures, hydrogenation reactions which destroyed the diphenol functionality predominated; these side-reactions occurred prior to hydrogenolysis of the C-S bond. Desulfurization of V also increased with temperature, but hydrogenation of the aromatic ring was not observed at T ≤25°C.