This paper presents a summary of our research into pillared clays. Studies on the optimum conditions for the preparation of pillared clays with aluminium polyoxycations are described. Incorporation of Ga into the oligomeric Al- cations resulted in materials with a greater thermal stability than conventional Al₂O₃- pillared montmorillonite. The activity and selectivity in hydro- isomerization and hydrocracking reactions of n-heptane were tested on bifunctional metal- acid catalysts of Al- and Al-Ga-PILCs. The results showed higher catalytic conversion at high temperatures, as well as greater selectivity towards isomerization on the Al-Ga-catalyst. On the other hand, montmorillonite pillared with polyoxycations of Al and AlGa has been modified with Ce, and the effect of the presence of the Ce³⁺ ion on the activity of catalysts obtained from the PILC products by impregnation with Pt has been investigated. Through acidity studies and catalytic tests the presence of Ce has been found to produce a substantial increase in the conversion of n-heptane and in the selectivity towards the cracking products. Also, evaluation of these catalysts by reaction of gasoil on vacuum has been carried out in MAT (microactivity test) system simulating the plant conditions for oil cracking. Furthermore, the catalytic activity and selectivity of Al- and Ga- Al-PILC were investigated for the alkylation of toluene with methanol. This reaction provides an example of acid catalysis, whose results also allow an evaluation to be made of the number and strength of the acid centers of the different catalysts.