Cells and organisms are complex machines driven by a set of dynamic biological events tightly orchestrated in space and time. Our understanding of their inner workings is intricately related to our ability to observe how their constituents organize and interact. Despite spectacular developments in biological imaging and probe design, many biologically relevant molecules and processes remain invisible. We are interested in inventing new chemogenetic tools for observing and controling biomolecules and dynamic biochemical events in live cells and tissues. These tools can allow biologists to address questions ranging from fundamental mechanisms to the causes of disease and the development of novel therapeutics.