The electrical conductances of three large-ion salts, tetraphenylphosphonium chloride (TPPC), tetraphenylphosphonium bromide (TPPB), and sodium tetraphenylboride (STPB), have been measured in water and each of the C-1 to C-4 alcohols at different temperatures. The molar conductivities of the large ions TPP+ and TPB- vary inversely with the solvent viscosity eta and with the carbon number N of the solvent molecules : (N + 1)(1/2)eta lambda(0) = constant. The value of this constant is slighty dependent on the chain structure of the alcohol : for TPP+, 28.6 (10(-7) Pa . s . S . m(2)/mol) in 1-alkanols, 30.0 in 2-alkanols, 30.4 in isobutanol, 26.9 in tert-butyl alcohol; for TPB- the respective values are 30.0, 31.5, 31.9, and 27.9. In water the values of (N + 1)(1/2)eta lambda(0) Of TPP+ (18.4) and TPB- (17.7) are the lowest, while the values for the small ions (44.6, Na+; 69.8, Br-; 67.9, Cl-) are the highest among all the solvents. In alcohols and wafer, the activation energies for molar conductivities (E(Lambda 0)) of the three salts are nearly the same as those of E(eta) of the solvents, with one exception. In tert-butyl alcohol the values of E(Lambda 0) (21 kJ/mol, TPPB; 22, TPPC; 19, STPB) are similar to those of the corresponding salts in other butanols and much lower than E(eta) of tert-butyl alcohol (31 kJ/mol). The activation energy of diffusion of the large tetraphenyl ions through the butanols, the molecular sizes of which are much smaller than the tetraphenyl ions, is relatively insensitive to the molecular structure of the butanols.