Abstract:The observed experimental parameters such as density (ρ), viscosity (η) and ultrasonic velocity (U) of ternary liquid mixtures of substituted benzenes such as chlorobenzene, bromobenzene, nitrobenzene, ethylbenzene and toluene added in the fixed binary solvent mixtures of (ratio 4:2) acetophenone and 1-heptanol at 303.15, 308.15 and 313.15K were determined. The observed experimental data have been utilized to evaluate some of the excess thermo acoustical parameters such as adiabatic compressibility (β E ), intermolecular free length (Lf E ), free volume (Vf E ), internal pressure (πi E ), Gibb's energy (∆G E ), viscosity (η E ) molar volume (Vm E )and Grunberg's Nissan interaction parameter (d). It is eventually observed that weak molecular association between acetophenone and 1-heptanol is through hydrogen bonding and substituted benzenes through weak dipole-dipole interactions. The existence of formation of donor -acceptor complexes in the present study has been identified and promptly discussed. Further, the impact due to the elevation of temperature on these liquid systems has also been interpreted.