The complete H-1,C-13 and N-15 NMR assignments of two closely related quinoacridinium salts, 8,13-diethyl-6-methy1-8H-quino[4,3,2-kl]acridinium iodide and, 8,13-diethyl-3,6,11-trimethyl-8H-quino[4,3,2-kl]acridinium iodide, are described. The multinuclear 1D NMR and 2D shift-correlated NMR techniques HMQC, HSQC and HMBC were applied, accompanied by ab initio GIAO CPHF calculations of shielding constants. Copyright (C) 2000 John Wiley & Sons, Ltd.