Two air and water stable hydrophobic ionic liquids N-alkyl-4-methylpyridinium bis (trifluoromethylsulfonyl) imide ([C n 4mpy][NTf2], n= 2, 4) were synthesized and characterized. The density, electrical conductivity, and dynamic viscosity were measured and estimated in the range of T=(278.15 to 363.15) K. The melting temperature, glass transition temperature, and decomposition temperature of the two ILs were determined ...