Two new, octadentate, water- soluble, macrocyclic ligands, 1,4,7,10-tetrakis(( 2 S)- ( -)- 2- hydroxy- 3-[ 3'-(N, N, N-trimethylammonium)phenoxy]- propyl)- 1,4,7,10- tetraazacyclododecane tetratriflate, (( S)- tmappc12 triflate, L-1 triflate) and 1,4,7,10-tetrakis((2S)-(-)-2-hydroxy-3-[2'-sulfo-4'-methylphenoxy]- propyl)-1,4,7,10- tetraazacyclododecane, ((S)-sthmppc12, (LH4)-H-2) have been prepared with a view to using them to study anion sequestration in aqueous solution. Their p K a and metal-ion binding constant values with a range of alkaline earth, transition, and post- transition metals are reported. The eight- coordinate, water- soluble Cd(II) complexes of (L-1)(4+) and (L-2)(4-), [ CdL1](CF3SO3)(6) and (NH4)(2)-[ CdL2], the former cationic and the latter anionic, have both been shown to be capable of acting as anion receptors in aqueous solution. The binding constant values ( log( K/M-1) given in parentheses) for binding by the cationic receptor to a range of aromatic anions in water are p-nitrophenolate (1.7), p-formylphenolate (2.1), p-nitrobenzoate (3.0), p-aminobenzoate (4.5), p-dimethylaminobenzoate (> 4.5), D- and L-tryptophanate (1.6, 2.2), phenoxyacetate (2.1), and acetate (2.3). With the anionic receptor, nonzero binding constants were only measurable for p-nitrobenzoate (similar to 0.4), p-aminobenzoate ( 2.0), and p-dimethylaminobenzoate ( 1.8). By reference to the X-ray determined structures of related, but water- insoluble inclusion complexes, anion retention is thought to occur within a hydrophobic cavity, with four convergent hydroxy groups at its base, which develops in (L-1)(4+) and (L-2)(4-) through the juxtapositioning of aromatic rings that occurs as a consequence of octadentate coordination.