Disclosed is a salt of amonafide or amonafide analogs represented Structural Formula (I): ##STR1##

• R1 is —(CH₂)_nN⁺HR3R4 X^- or R1 is —(CH₂)_nN⁺HR3R4 X^- or —(CH₂)_nNR3R4 when R2 is —N⁺HR6R7.
• R2 is —OR5, halogen, —NR6R7, —N⁺HR6R7 X^- sulphonic acid, nitro, —NR5COOR5, —NR5COR5 or —OCOR5;
• R3 and R4 are independently H, C1-C4 alkyl group or, taken together with the nitrogen atom to which they are bonded, a non-aromatic nitrogen-containing heterocyclic group;
• each R5 is independently —H or a C1-C4 alkyl group;
• R6 and R7 are independently H, C1-C4 alkyl group or, taken together with the nitrogen atom to which they are bonded, a non-aromatic nitrogen-containing heterocyclic group;
• n is an integer from 0-3; and
• X^- is the carboxylate anion of an organic carboxylic acid compound.

Also disclosed are methods of preparing certain compounds represented by Structural Formula (I).