The real ~i'j and imaginary ~',i parts of complex dielectric constant E~i of some aprotic polar molecules (j) like dimethylsulphoxide (DMSO) : N, N-diethylformamide (DEF) : N, N-dimethylformamide (DMF) and N,N-dimethylaeetamide (DMA) in benzene (i) for different weight fractions wi's of solutes are located at different temperatures under nearly 10 GHz electric field together with the static and infinite frequency dielectric constants eo~j and E~ij. All the molecules show the double relaxation times "q and "c_~ for rotations of their flexible parts and the whole molecules by the single frequency measurement technique. The "t t in agreement with reported "t signifies that a part of the molecule is rotating under 10 GHz electric field. It is also supported by energy parameters AH~, AS~ and AF~ measured from In (z T) against 1/T curves for DMSO. The relative contributions c~ and c 2 towards dielectric relaxations for "q and "t 2 are ascertained from Frrhlich's equations and graphical technique. The corresponding dipole moments t12 and gl of the whole and the flexible part of the molecule are obtained from z 2 and "q and the slope [3 of high fiequcncy conductivity (Y*i against wi in order to compare with the measured static gs and reportcd It'S. ]a,'s are found to agree with ~tj and static g~. The molecular conformational structures are obtained by la~ from a~/lathoo by considering mesomeric and inductive effects of the substituent polar groups, bt,,~.o'S are obtained from available bond moments and bond angles. The comparison of all the g's shows little dependence on electric field frequency.