Disclosed herein is a chemical delivery system having: i) a cargo compound comprising a first reactive moiety covalently bonded to a first enrichment moiety and a tethered cargo moiety, wherein the first reactive moiety is bonded to the tethered cargo moiety via a cleavable linker; and ii) a trigger compound comprising a second reactive moiety covalently bonded to a second enrichment moiety and a cargo-releasing moiety. The first enrichment moiety and the second enrichment moiety cause an increase in concentration of the cargo compound and the concentration of the trigger compound at a target site, causing a bimolecular reaction between the first reactive moiety and the second reactive moiety to form a cyclization precursor compound. The cargo moiety is then released from the cyclization precursor compound in a unimolecular cyclization reaction. Methods for treating conditions such as cancer, inflammatory conditions, and infections with the chemical delivery systems are also described.