System design. The self-dividing, active droplets are based on complex coacervation regulated by a fuel-driven chemical reaction cycle. We used the peptide acetyl-FRGRGD-OH as polycation (peptide) in which F means phenylalanine, R means arginine, G means glycine, and D means aspartic acid. Upon adding 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC, fuel), the C-terminal aspartic acid reacts to its corresponding cyclic anhydride state-the peptide activation. The fuel is converted into its corresponding urea form (EDU, waste) in the activation. The cyclic anhydride of the activated peptide spontaneously hydrolyzes to yield the original peptide-the deactivation. The peptide is zwitterionic with a net charge of 0, whereas the activated peptide has an overall charge of +2. The cationization of the peptide enables it to form complex coacervates with polyanions through electrostatic interactions (Scheme 1). This work explores polystyrene sulfonate (PSS) of different lengths as polyanion. The transient, activated peptide is produced as long as fuel is present and the complex coacervate droplets can be sustained. However, the droplets dissolve as soon as the peptide deactivation outcompetes activation. Coupling a fuel-driven reaction cycle with droplet material formation implies that droplets emerge in response to chemical fuel. Thus, in fueling-starvation experiments, a batch of fuel is added, and the droplets have a finite lifetime.