A graphical method is used to determine the double relaxation times τ 2 and τ 1 for the rotation of the flexible part and the whole molecule of some long-chain alcohols in n-heptane under 24.33 GHz (K-Band), 9.25 GHz (X-Band) and 3.00 GHz (J-Band) electric fields on the basis of Debye and Fröhlich models. The fixed τ 1 and τ 2 at those frequencies are compared to the average τ 1 and τ 2 measured by the single frequency method of Saha et al. [U. Saha, S.K. Sit, R.C. Basak, S. Acharyya. J. Phys. D: Appl. Phys. 27 (1994) 596.] and reported average τ's. This reveals the material properties of the chemical systems in identical environments. τ's thus obtained agree well with the reported average τ's at three different frequencies for most of the alcohols. This at once indicates the whole molecular rotation of the dipolar molecules at those frequencies. The dipole moments μ 1 and μ 2 are, however, measured from the linear coefficients β of hf susceptibilities χ ij ′ curves against weight fractions w j of the alcohols at all the frequencies in terms of the graphically obtained τ 1 and τ 2 and the reported τ by the existing methods. Theoretical dipole moments μ theo from the available bond angles and bond moments are also determined. The slight disagreement among the μ theo , reported and estimated μ indicates the existence of the inductive, electromeric and mesomeric effects of the substituent polar group -OH attached to the parent ones.