Conductivities of some tetraalkylammonium halides, viz. tetrabutylammonium bromide (Bu 4 NBr), tetrapentylammonium bromide (Pen 4 NBr), tetrahexylammonium bromide (Hex 4 NBr) and tetraheptylammonium bromide (Hep 4 NBr) were measured at 298.15K in THF+C 6 H 6 mixtures with 10, 20, 30 and 40mass% of C 6 H 6 . A minimum in the conductance values was observed as concentration increases, which dependent both on the salt and the solvent. The observed molar conductivities were explained by the formation of ion-pairs (M + +X − ↔MX, K P ) and triple-ions (2M + +X − ↔M 2 X + ; M + +2X − ↔MX 2 − , K T ). A linear relationship between the triple-ion formation constants [log(K T /K P )] and the salt concentrations at the minimum conductivity (logC min ) was given for all salts in C 6 H 6 +THF mixtures. The formation of triple-ions might be attributed to the ion sizes in solutions in which coulombic interactions and covalent bonding forces act as the main forces between the ions (R 4 N + ⋯ X − ).