Ongoing efforts towards the development of CO-based therapeutics have resulted in the generation of novel CO prodrugs that release CO via different triggers or stimuli. Here in, we designed and synthesized organic CO prodrugs with a tethered cytotoxic agent to achieve a co-delivery of CO and the cytotoxic drug under physiological conditions by leveraging on the inverse electron-demand Diels-Alder reaction as the trigger. We also attempted to characterize, kinetically and spectroscopically, some of the organic CO prodrugs synthesized by our lab. The results showed that these prodrugs released CO under near physiological condition with controllable and tunable release rate.