Seven chelating agents were synthesized. The complexation properties of these reagents with divalent metals (Cu2+, Co2+, Ni2+, Zn2+) were investigated in dioxane–water (75% dioxane, 25% water), and the complex formationconstants were compared with those of 8-quinolinol as a reference chelating agent. These sulfonamidoquinoline reagents formed ML and ML2 type complexes, and the order of complex stabilities