In this paper we report excess molar enthalpies H-m(E) and excess molar volumes V-m(E) of the polar solvents N-methyl-2-pyrrolidinone (C5H9NO), N,N-dimethylformamide (C3H7NO), and dimethyl sulphoxide (C2H6SO) with 1-hexyne, or 1-heptyne, or 1-octyne at T = 298.15 K. The H-m(E) values are negative for the mixtures of N-methyl-2-pyrrolidinone, or N,N-dimethyl formamide with a 1-alkyne and become more positive with increasing 1-alkyne chain length. The H-m(E) values are positive for dimethyl sulphoxide with a 1-alkyne and increase with increasing chain length. The V-m(E) results are negative for all the systems studied here. The ERAS model (extended real associated solution) has been applied to these mixtures, and the results are discussed in terms of intermolecular associations.