• Case study 1: (2-chloro-N-(4-fluorophenyl)-N-methylacetamide) (17) -£392/g. • Case study 2: benzyl 4-(2-chloro-N-(4-(methoxycarbonyl)phenyl)acetamido)-piperidine-1carboxylate ( ) -£1960/50g. • Case study 3: 2-chloro-N-(2-fluoro-4-nitrophenyl)-N-methylacetamide (21) -£303/g. • Case study 4: 3-chloro-N-(4-methoxyphenyl)-N-methylpropanamide (23) -£189/g. As the starting material is the most expensive reaction component, this was the only factor taken into consideration -other costs were not considered, but would also lead to a significant increase in cost: catalyst, ligands, solvents, energy etc. It is assumed that a 2 mL reaction slug of 0.09 M starting material solution is used for each experiment in a flow reactor. For kinetic experiments in flow, this would also be roughly equivalent to the amount of reaction material ideal for one batch experiment with multiple time-point sampling. The addition of skilled labor and cost of time have also not been considered, but would incur a significantly higher cost for these other techniques as this scales with the number of experiments conducted. More process understanding could be gained from these techniques and the additional datapoints, but for medicinal chemistry applications of intermediate reaction optimization, the costs are substantially cheaper using MTBO.