A common problem with cancer chemotherapy is unwanted side effects. There are many approaches to targeted therapy, and we have focused on using light to target the cytotoxic effects only in the vicinity of the tumor. To target the chemotherapeutic dose, we have developed a new strategy for controlled drug release called photocaged permeability. We can can prevent a known anticancer drug from entering and killing cancer cells by attaching a hydrophilic caging group which prevents it from entering cells. Upon illumination the caged drug enters the cells and is able to exert its cytotoxic effect. We have also developed a folate-receptor targeted version of our conjugate. Although the basic chemistry of photocaged permeability requires UV light, we have adapted our method to enable near-IR release of doxorubicin using lanthanide-doped upconverting nanoparticles.