The ion exchange equilibria of Br- on three strongly basic anion exchange resins of different exchange capacities and different cross-linking degrees by five alkanoates (MCm), a phosphate, and eight alkanedioates (DCn; m,n = number of carbon atoms) were analyzed, and the selectivity coefficients for their monoanion and dianion, K-11 and K-21 were evaluated as a function of percent exchange (%E). The decrease in the K-11 values of MCm, with an increase in %E was attributed to the interference with hydration of MC, in the resin phase, while the increase in the K-11 values of DC to the intermolecular hydrogen bonding between exchanged acidic anions. The log K-21 values of DC at %E = 0 plotted against n showed the minimum rather than the maximum as described previously. The reason has been discussed in terms of the hydrophobic interaction of DC with the polymer matrix, intramolecular hydrogen bonding, and the charge density.