In general, after the synthesis stage, the fresh synthesized MOF is washed using the same solvent used in the synthesis, or a different solvent. At this stage the unreacted substances, modulators, and other chemicals are washed out. But, to activate the MOF, the solvent must be completely removed from the inner pores, which is often challenging, especially if the MOF is very weak or has large pores as was discussed previously. The easiest approach is to remove the solvent directly after the synthesis stage without the need to go for subsequence complex activation processes that would consume huge amounts materials or demand considerable time and efforts. Nevertheless, only few MOFs were successfully activated directly after the synthesis, as shown in the pie chart (Figure ), grouped under the category "direct activation". This because, the synthesis liquid medium is usually comprising strongly interacting solvents with high surface tension or boiling point, which entail harsh activation conditions. So, for a MOF to survive such harsh conditions it has to possess great robustness. In addition, those structures washed using the same synthesis solvent were also included in this category. While if the as-synthesized MOF washed with a different solvent then it was added to the "solvent exchange" category. In other words, the "direct activation" class include MOFs that directly activated after separation from the mother liquor, and those washed using the same synthesis solvent.