The present invention relates to dispersants for dispersing a particulate solid for millbases, paints and inks. The present invention provides a composition containing a particulate solid, a polar organic medium and a compound or salts thereof for formula T-(A)m(B)n—X—Z-Q(0-p) wherein T is hydrogen or a polymerization terminating group; A is the residue of a hydroxy carboxylic acid or lactone thereof; B is the residue of an amino carboxylic acid; X is a direct bond or a divalent group; Z is an acidic or basic group or a moiety which contains an acidic or basic group; Q is an optional residue of an oxide, urea or a dibasic acid or anhydride thereof; m and n are positive integers; and p represents the number of residual amino and/or imino groups in Z.