Dielectric relaxation studies of binary ($jk$) polar mixtures of tetrahydrofuran with $N$-methyl acetamide, $N,N$-dimethyl acetamide, $N$-methyl formamide and $N,N$-dimethyl formamide dissolved in benzene(i) for different weight fractions ($w_{jk}$’s) of the polar solutes and mole fractions ($x_{j}$ ’s) of tetrahydrofuran at 25◦C are attempted by measuring the conductivity of the solution under 9.90 GHz electric field using Debye theory. The estimated relaxation time ($\tau_{jk}$’s) and dipole moment ($\mu_{jk}$’s) agree well with the reported values signifying the validity of the proposed methods. Structural and associational aspects are predicted from the plot of $\tau_{jk}$ and $\mu_{jk}$ against $x_{j}$ of tetrahydrofuran to arrive at solute–solute (dimer) molecular association upto $x_{j} = 0.3$ of tetrahydrofuran and thereafter solute–solvent (monomer) molecular association upto $x_{j} = 1.0$ for all systems except tetrahydrofuran + $N,N$-dimethyl acetamide.