The light-induced photolysis of [Zn-(NTAdeCage)](-) generates a temporally controlled burst of Zn2+, which is rapidly chelated in situ by the free ligand Zincon(2-). The [Zn(Zincon)](2-) coordination progress is monitored using absorption spectroscopy in bulk aqueous buffer and reverse micelle environments. The [Zn(NTAdeCage)](-) photocage and free ligand Zincon(2-) have different reverse micelle locations that affect the [Zn(Zincon)](2-) formation at the nanoscale compared to the bulk aqueous buffer. The formation of [Zn(Zincon)](2-) in a bulk aqueous buffer is more efficient despite the released Zn2+ and Zincon(2-) being physically closer within reverse micelles. The observed reduction of complex formation is attributed to the interfacial partitioning of Zincon(2-), distinct from the Zn2+ photocage in the water pool, requiring diffusion for the species to meet to form [Zn(Zincon)](2-). This work introduces a proof-of-concept methodology to experimentally measure fast chelation reactions in confined spaces and thus provides an approach to exploring cellular responses.