Abstract: A series of semicarbazones and thiosemicarbazones have been prepared and their ¹H and ¹³C spectra have been determined.The HMO method has been used to calculate the π-electron densities ρ_x for this series.It has been shown that a good linear relationship exists between δ_c and the π-electron densities ρ_x or the Hammett σ_p constants and between δ_H and σ_p.However the chemical shifts of their aromatic protons and aromatic carbonic atoms have been calculated bythe empirical formulas δ_c(1)=δ_c(0)+∑_jS_jiandδ_H=7.41-∑S.