This disclosure relates to aromatic ester plasticizers, including methyl biphenyl carboxylic acid esters of alcohols having an average carbon number ranging from 9.0 to 9.4 and a degree of branching of 3.0 or less, preferably 2.2 or less, to mixtures of such plasticizers, to compositions comprising the plasticizers and to thermoplastic polymer, such as polyvinylchloride, that contains the plasticizers.