Abstract The real ɛ′ij and imaginary ɛ″ij parts of complex dielectric constant ɛ*ij of some aprotic polar molecules (j) like dimethylsulphoxide (DMSO) : N,N-diethylformamide (DEF) : N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) in benzene (i) for different weight fractions wj's of solutes are located at different temperatures under nearly 10 GHz electric field together with the static and infinite frequency dielectric constants ɛoij and ɛoeij. All the molecules show the double relaxation times τ1 and τ2 for rotations of their flexible parts and the whole molecules by the single frequency measurement technique. The τ1 in agreement with reported τ signifies that a part of the molecule is rotating under 10 GHz electric field. It is also supported by energy parameters ΔHτ, ΔSτ and ΔFτ measured from ln (τ T) against 1/T curves for DMSO. The relative contributions c1 and c2 towards dielectric relaxations for τ1 and τ2 are ascertained from Fro¨hlich's equations and graphical technique. The corresponding dipole moments μ2 and μ1 of the whole and the flexible part of the molecule are obtained from τ2 and τ1 and the slope β of high frequency conductivity σij against wj in order to compare with the measured static μs and reported μ's. μ1's are found to agree with μj and static μs. The molecular conformational structures are obtained by μcal from μs/μtheo by considering mesomeric and inductive effects of the substituent polar groups. μtheo's are obtained from available bond moments and bond angles. The comparison of all the μ's shows little dependence on electric field frequency.