From experimental data (densities, speeds of sound, and refractive indices) over the temperature range (283.15 to 313.15) K for the binary mixtures formed by an isomer of chlorobutane (1-chlorobutane, 2-chlorobutane, 2-methyl-1-chloropropane, or 2-methyl-2-chloropropane) plus diisopropyl ether, the following properties have been calculated: excess volumes, excess isentropic compressibilities, and refractive index deviations. The excess properties and deviations were fitted using the Redlich−Kister polynomial equation. The excess volumes and excess isentropic compressibilities for the four systems are all negative over both the composition and temperature ranges, whereas the refractive index deviations are always positive.