Coordination complexes (including discrete coordination complexes and coordination polymers) have demonstrated excellent performance in drug delivery. This review outlines recent advances of discrete coordination complexes, bulk coordination polymers, and nanoscale/microscale coordination polymers in drug delivery. Specifically, rationale and mechanism of coordination complexes in drug delivery are summarized in this contribution. In this review, we discuss applications of these coordination species in drug delivery from perspectives in chemistry and pharmaceutical sciences, and an outlook of these coordination species of interest in drug delivery will also be proposed.