Via the co-hydrolysis of CrCl3 and AlCl3 in the presence of swollen Na-montmorillonite, pillared layer clays were prepared. The location of chromium in the pillars and in the primary pillaring agent, the Al-13-Keggin ion, was investigated by various methods (mid and far IR and Al-27 NMR spectroscopies). We found that isomorphous substitution of chromium for aluminium did not occur, rather co-hydrolysis and co-pillaring took place. Upon heat treatment the loss of outer-sphere water and dehydroxylation at higher temperatures resulted in the formation of bulky alumina pillars decorated with chromia species, The resulting material was used in the oxidation of 1-phenyl-1-propanol in the presence of tert-butylhydroperoxide as co-oxidant.