The transition energies (E-op) for the intervalence bands of the radical cations from N,N,N',N'-tetramethyl-p-phenylenediamine, 1,4-bis(9'-azabicyclo[3.3.1]non-3'-one-9-yl)benzene, and N,N,N',N'-tetramethyl-4,4'-diaminobiphenyl have been determined in eleven solvents varying in polarity from chloroform to acetonitrile. Assuming the Marcus-Hush two state model E-op = 2H(op), where H-op is the matrix coupling element between the charge-bearing dialkylamino units of these delocalized systems. H-op is detectably sensitive to solvent, varying 140, 70, and 110 cm(-1), respectively. A trend for dependence of H-op on the refractive index of the solvent (n) is observed, H-op increasing slightly as n(-1/2) increases. Empirical fit to the observed H-op values suggests that in addition to the n effect, there is quite compound-specific sensitivity to solvent donor number. Sensitivity of H to solvent is of similar magnitude for the localized bis(hydrazine) intervalence cation 22H(+), using Hush's method for evaluating H from the charge-transfer band parameters (we call this number H-H) The H-H values show the opposite solvent refractive index effect, H-op decreasing as n(-1/2) increases. However, when the extinction coefficient (epsilon(max)) correction suggested by the Kodak group is introduced into the Hush equation, a slight increase in H with n(-1/2) that is qualitatively similar to that found for the delocalized systems is obtained. This suggests to us that a refractive index correction to epsilon(max) should be used.