The concentration of the precursors was also studied: Al-PMOF was obtained with the same metal to ligand ratio except for different amounts of solvent, which also leads to a change of the pressure inside the reaction vessel. As a control, concentrations 1 and 2, possess the same volume but different metal and ligand concentrations (Table ). The analysis of the relative importance of experimental variables shows that concentration plays a major role on crystallinity. The lowest concentration (i.e., concentration 3, which also presents the largest amount of solvent, and thus highest pressure) is not suggested in generation 2, as it leads to relatively poor crystallinities in generation 1. It seems that the combination of low concentrations and high pressures in the reaction vessel are not beneficial for the MOF formation. On the other hand, if we compare concentrations 1 and 2, which possess the same volume, the highest concentration (i.e., concentration 1) tends to give better crystallinities overall, which may be positively correlated to the kinetics of the reaction 45 (Figure ). Color code is given for worst (brown) and best (dark green) samples. Generation 1 was ranked in terms of the crystallinity of each sample, while the success of generation 2 was determined by the yield as all samples proved to be highly crystalline. This proves the success of the GA in providing good crystallinity of all samples in just one generation.