Chemosensors are compounds that incorporate a receptor unit and a reporter unit in a single molecule. A chemosensor transforms the action of binding to a specific analyte into a readable signal. Chemosensors have enabled the study of molecular interactions in a range of different media and interfaces. This offers a non-invasive approach to observe living biological samples in real time without the sample being destroyed. For example, fluorescence-based chemosensors are designed to have a high sensitivity and specificity, allowing them to interact selectively with a single target within a complex biological environment. As a result, such chemosensors can be used for fluorescence imaging, allowing for high spatial and temporal resolution of biological samples. Consequently, chemosensors have been used for a broad range of applications including clinical diagnostics and for the detection of environmental, agriculture, and industrial pollutants, making them critically important for public health and safety.