Abstract Linear free energy relationships (LFER) were applied to the kinetic data and 13 C NMR chemical shifts in 4-[[(substituted phenyl)imino]methyl]benzoic acids. The correlation analysis for the kinetic data and substituent-induced chemical shifts (SCS) with σ using single substituent parameter (SSP), as well as inductive ( σ I ) and various resonance ( σ R ) parameters using dual-substituent parameter (DSP), were carried out. The presented calculations account satisfactorily for the polar and resonance substituent effects having similar contributions at all carbons studied. Negative ρ values were found for several correlations (reverse substituent effect). Exceptionally good Hammett correlation of 13 C NMR chemical shifts of azomethine carbon with electrophilic substituent constants σ + indicates a significant resonance interaction in the aniline part of molecules. The conformations of investigated compounds have been studied by the use of DFT method, and together with 13 C NMR chemical shifts and kinetic data, give a better insight into the influence of such a structure on the transmission of electronic substituent effects. New σ constants for substituted phenyliminomethyl group have been calculated.