A process for producing copolymers of a polymer and asymmetrically substituted compounds of bisanhydrohexitols, including the bisanhydrohexitol isosorbide. In a specific example, the AB monomer isosorbide 2-(4-carbomethoxybenzoate) is synthesized and copolymerized with polyester to form a copolyester. The asymmetrically substituted compounds provide a way of incorporating bisanydrohexitols that may be derived from natural sources into polymers.