Having gained preliminary insights into efficient acylation methods and the effect of nucleophilic catalysis, we shifted our attention towards the optimization of reaction parameters affecting the entire NaphPO4 / NaphAcPO4 reaction cycle (Figure ). Our objective was to gain a more detailed understanding and control of the system parameters. One of the most important parameters appeared to be the concentration of pyridine, which is why we monitored the system composition over time upon addition of four equivalents of acetic anhydride (Figure ). As expected, we found that the pyridine concentration had a positive effect on acylphosphate formation, and only a maximum yield of 38 % for NaphAcPO4 was observed in the absence of pyridine. As becomes evident from Figure , pyridine also has a strong effect on hydrolysis rates, which can be attributed to the fact that the acetylated pyridinium species plays a central role in both the acyl phosphate formation and its hydrolysis (as illustrated in Scheme S1). This finding highlights an evident advantage of a reaction cycle that is subject to (organo)catalysis, namely that the hydrolysis half-life of the transient acylphosphate can be fine-tuned from mere minutes to several hours, solely by varying the pyridine concentration. Pyridine catalysis also enables the generation of steady state mixtures under mild conditions, such as room temperature and neutral pH. Other parameters, including fuel equivalents, precursor concentration, temperature, and pH, were found to also affect the kinetics of the two reactions forming the reaction cycle and are depicted in more detail in the SI (Table and S5 and Figure ). In this context, it is worth noting that the system is robust across a broad range of parameters (even at elevated temperatures and from moderately acidic to alkaline conditions).