Vapor pressures of 1-(n-alkyl)-benzimidazoles with chain lengths from methyl to pentyl (C-1-C-5) have been determined as a function of temperature by the transpiration method. From these data, the molar enthalpies of vaporization (Delta H-g(l)m) were calculated, and a linear correlation with the number of carbon atoms was found. At a given temperature, 1-n-alkylbenzimidazole vapor pressures were found to decrease with the increasing length of alkyl chain, and the fused ring system was found to lower vapor pressures and increase heats of vaporization relative to the corresponding 1-n-alkylimidazoles.