The 13C NMR Substituent-induced Chemical Shifts (SCS) of aromatic carbons in 1,4-disubstituted benzenes were correlated with inductive and mesomeric effects, expressed in σI and σR (NMR) scales, and with charge alterations (Δ) provoked by introducing a new substituent (X) at position C-1. 105 different compounds with groups attached to C-1 (X) and C-4 (Y) in a sequence: NMe2, NH2, OMe, F, Cl, Br, Me, H, CF3, CN, C(O)OEt, C(O)Me, NO2 and CHO were studied. Correlations of σI and σR with SCS and with Δq, and of SCS with Δq, showed statistical relevance just for C-4. SCS and Δq were correlated only with σR for C-2. No correlation was found for C-1 (ipso-carbon), except between Δq and σR, while for C-3 the occurrence or not of any correlation was strongly dependent on the classes of compounds, fixed by the substituent at C-4 (Y).452135Bromilow, J., Brownlee, R.T.C., Craik, D.J., Sadek, M., Taft, R.W., (1980) J. Org. Chem., 45, p. 2429Fadhil, G.F., (1992) Z. Naturforsch., 47 A, p. 775Bromilow, J., Brownlee, R.T.C., Craik, D.J., Sadek, M., (1986) Magn. Reson. Chem., 24, p. 862Ludwig, M., Wold, S., Exner, O., (1992) Acta Chem. Scand., 46, p. 549Brownlee, R.T.C., Sadek, M., (1981) Aust. J. Chem., 34, p. 1593Ehrenson, S., (1979) J. Org. Chem., 44, p. 1793Krygowski, T.M., Häfelinger, G., Schüle, J., (1986) Z. Naturforsch., 41 B, p. 895Bock, C.W., Trachtman, M., George, P., (1985) J. Mol. Struct., 122, p. 155Sadova, N.I., Vilkov, L.V., (1982) Russ. Chem. Rev. (Engl. Transl.), 51, p. 87March, J., (1992) Advanced Organic Chemistry, 4th Ed., pp. 19-22. , Wiley, New YorkStewart, J., (1990) "Mopac Manual". 6th Ed., , Frank J. Seiler Research Laboratory, U. S. Air Force AcademyBurkert, U., Allinger, N.L., (1982) Molecular Mechanics, 1st Ed., , American Chemical Society, Washington, chapter 3Dodge, M., Kinata, C., Stinson, C., (1995) MS Excel 5 for Windows, 1st Ed., , Microsft Press-Makron Books, São PauloBox, G.E.P., Hunter, W.G., Hunter, J.S., (1978) Statistics for Experimenters, , Wiley, LondonCanto, E.L., Rittner, R., (1990) I Jornada Brasileira de Ressonância Magnética, , Rio de JaneiroBromilow, J., Brownlee, R.T.C., Lopez, V.O., Taft, R.W., (1979) J. Org. Chem., 44, p. 4766Wells, P.R., Ehrenson, S., Taft, R.W., (1968) Prog. Phys. Org. Chem., 6, p. 147Mendenhall, W., Sincich, T., (1988) "Statistics for the Engineering and Computer Sciences". 2nd Ed., , Deelen-Macmillan, London, chapter 11Hehre, W.J., Taft, R.W., Topsom, R.D., (1976) Prag. Phys. Org. Chem., 12, p. 159Budesínsky, M., Johnels, D., Edlund, U., Exner, O., (1991) Collect. Czech. Chem. Commun., 56, p. 368