The present invention relates to compounds of formula I, which are unsymmetrical aromatic ether diacids, and polymers formed from the same. [R'--(Y).sub.p--O].sub.q--Ar--[O--(X).sub.r--R'].sub.s IPolymers formed from the functionalized unsymmetrical aromatic ether diacids are expected to have controllable degradation profiles, enabling them to release an active component over a desired time range. The polymers are also expected to be useful in a variety of medical applications.