Shining a Light on Benzo[c][1,2,5]thiadiazole Photocatalysts

The benzo[c][1,2,5]thiadiazole (BTZ) group is a strongly electron accepting unit that has primarily been investigated for application in photovoltaic systems or as fluorescent bioimaging agents or sensors. The strongly electron accepting nature of the BTZ group, in combination with its excellent photostability and options for chemical derivatisation, has kindled interest within the photochemistry community with regards to using this unit as a prospective building block in π-conjugated electron donor-acceptor photocatalysts. The aim of this review is to highlight the research surrounding the development of photocatalytic systems based on the BTZ group. This will include discussing chemical reactions that can be used to synthesise or derivatise the BTZ motif, as well as highlighting methods that have been used to alter the structural, photophysical or optoelectronic properties of electron donor-BTZ electron acceptor systems. Subsequent discussion of the photocatalytic applications will span both homogeneous photocatalysts (molecules, molecular cages and linear polymers) and heterogeneous materials (such as crosslinked organic polymers, covalent organic frameworks, and metal-organic frameworks) containing the BTZ group and structurally related groups.