In order to correlate and predict interfacial mass transfer rates for ionic liquids and organic components, transport properties are required at various temperatures and, importantly, compositions. Here, the viscosity of mixtures of 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([HMIm][Tf2N]) with 1-octene to the liquid-liquid saturation limit were measured at four different isotherms [(10, 25, 50, and 75) degrees C]. The viscosity of a [HMIm][Tf2N] + 1-octene mixture decreases up to 33 % over the pure ionic liquid in the temperature range studied. The computed viscosity deviation ("excess viscosity") demonstrates a negative trend throughout the composition range and diminishes with increasing temperature. The self-diffusivity of both 1-octene and [HMIm][Tf2N] (cation) were measured at (25 and 50) degrees C and increased up to 40% with increasing composition of 1-octene. The self-diffusivities were of the order of (10(-11) and 10(-10)) m(2).s(-1) for the cation and 1-octene, respectively.