The isentropic compressibilities KS, excess isentropic compressibilities , and excess molar volumes VE have been determined from the measurements of speeds of sound u and densities ρ of seven binary mixtures of acrylonitrile with ethanenitrile, methyl acetate, ethyl acetate, n-butyl acetate, dimethylformamide, dimethylacetamide, and dimethyl sulfoxide at 303.15 K. Variable-degree polynomials were fitted to the results. The values of the excess functions indicate a varying extent of molecular interaction and interstitial accommodation between unlike components. The experimental speeds of sound have been analyzed in terms of the collision factor theory of Schaaffs (Molekularakustik; Springer-Verlag: Berlin, 1963) and the free length theory of Jacobson (Acta Chem. Scand. A 1952, 6, 1485−1498).