Here, the use of 1,4-benzendicarboxylic acid (BDC) is employed as linker to obtain the "native" UiO-66. However, as schematized in Figure , mono-and disubstituted linkers can be employed, featuring -NH2, -NO2, -COOH groups, as well as different halogen heteroatoms. All of these chemical modifications alter not only the pore chemistry but also its accessibility, since the dangling groups can occupy either the pore entrance or the pore volume. In addition, likers can also be used in different proportions, as shown for the UiO-66-NH2 derivative, with relatively straightforward control on the final composition of the MOF. However, special care must be taken when exploring the functionalization of the structure, since it can also affect the stability of the MOF. For example, the use of 2-sulfonylterephthalic acid (BDC-SO3H) as linker creates a structure that collapses upon removal of the residual solvent from the pores, because of the high charge state. The collapse can be avoided if the content of this linker is reduced below 40 %. 82