Cell division is an important fundamental biological process required for life, growth and development. It requires the coordinated action of many different cellular machines and regulators. Although we have known that cells divide since the concept of the cell was first established, there are many outstanding mechanistic questions, especially in cytokinesis, the final step where cells physically divide. Cytokinesis has been difficult to study because it is a complex, rapid and dynamic process. Many key proteins also perform important functions earlier in the cell cycle, which makes it challenging to investigate their roles during cytokinesis using traditional techniques. New approaches are therefore needed to overcome these barriers to deeper understanding, one of which is to develop probes that act rapidly and with high temporal control.