For three derivatives of 4-amino antipyrene, density, viscosity and ultrasonic velocity are measured at 318.15 K in 1,4-dioxane (DO) and dimethylformamide (DMF). From these experimental data, various acoustical properties such as specific impedance (Z), isentropic compressibility (kappa(s)), Rao's molar sound function (R-m), the van der Waals constant (b), molar compressibility (W), intermolecular free length (L-f), relaxation strength (r), relative association (R-A), free volume (V-f), etc. and apparent molar volume and apparent molar compressibility were calculated. The results are interpreted in terms of molecular interactions occurring in the solutions. It is observed that in 1,4-dioxane solutions, solute-solute interactions exist whereas solvent-solute interactions predominant in DMF system. (C) 2003 Elsevier B.V. All rights reserved.