AbstractThe stability constants for several metal complexes (Cu(II), Ni(II), Zn(II), Co(II), Fe(III), Al(III)) of terpolymers from diallyl[3‐formyl (or 3‐acetyl‐) 4‐hydroxybenzyl]methylammonium chloride, diallyldimethylammonium chloride, and sulfur dioxide were determined by potentiometric titration.The results are discussed comparing the stability constants with those of o‐hydroxybenzaldehyde and o‐hydroxyacetophenone derivatives.