AbstractThe excellent linearity (R2 = 0·997) of a plot of pKa values for 17 m− and p‐substituted benzyl phenyl sulfones, GC6H4CH2SO2Ph, vs. those for the corresponding arylacetonitrile, GC6H4CH2CN, demonstrates that substituent solvation and substituent solvation assisted resonance (SSAR) effects for p‐CN, p‐COPh, and p‐SPh are nearly identical in these two substrates. The PhSO2 group in PhCH2SO2Ph increases the BDE of the α‐CH bond by 2 kcal/mol, relative to toluene. The α‐CH bonds in GC6H4CH2SO2Ph sulfones are stabilized by 1–2 kcal/mol by acceptor G′s (m‐CN, p‐CN, m‐CF3, p‐CF3), but weakened by 1 and 5 kcal/mol, respectively, by donors (p‐OMe and p‐NMe2). The GC6H4CH2SO2Ph+. radical cation with G = H has a pK = −25. Its acidity is increased when G is an acceptor by as much as 9 to 10 kcal/mol (G = 3‐CN, 3‐CF3, 4‐CF3, 4‐NO2), but is decreased when G is a donor by as much as 33 kcal/mol (G = NMe2). When G = 4‐SPh the radical cation is stabilized, relative to G = H, by a larger amount (25 kcal/mol) than when G = 4‐OMe (18 kcal/mol). Structural changes along the series PhCH2SO2Ph, 2‐naphthyl‐CH2SO2Ph, 9‐anthryl CH2SO2Ph cause negligible changes in the acidities of these acids, but sizable decreases in the acidities of the corresponding radical cations. Introduction of a phenylsulfonyl group into the methyl group of 9‐methylanthracene or the 9‐position of fluorene or xanthene increase the BDEs by 3, 2, and 7 kcal/mol, respectively. These effects of PhSO2 groups are compared and contrasted with those of CN groups.