Light activated drugs are part of a new arsenal that has been actively pursued in the past decades against different types of diseases. When activated by non-ionizing radiation (visible light), harmless drugs can be quickly turned into very potent chemicals that can lead to the killing of cells, either via necrosis or apoptosis. Rather than depending on the selective reactivity between such drugs and the diseased cells/tissues, the search for light activated drugs has been mainly focussed on drugs that will selectively biodistribute towards the diseased cells or tissues prior to being activated by light. The selectivity would thus be determined not by the chemical reactivity of the drug towards different types of cells or tissue as is the case of many anti-tumour drugs, but rather by the process of selective retention of the drug in the unwanted tissue prior to its activation by light. Such a process could considerably reduce the damaging effects on normal tissue that often accompanies chemo- or radiation therapy.