Experimentally measured values of dielectric constant () at a frequency of 455 kHz and temperature 303.16K in binary polar mixture of acetyl acetone and of di-iso-butyl ketone in chlorobenzene, bromobenzene and toluene have been used to compute the mutual correlation factor (gab), the excess molar polarization (ΔP) and the Gibb's free energy of mixing (ΔGab) using Winkelmann-Quitzsch equations. The results are utilised in interpreting the molecular association and hence the nature of clusters involving unlike molecules.