Two approaches were considered for the preparation of Fe-containing composites based on montmorillonite and comparison of their structural, physicochemical and catalytic properties. The first approach (Si,Fe x -Mt materials) was based on the intercalation of Cheto montmorillonite (Mt) by 3-aminopropyltriethoxysilane (APTES) and FeCl 3 via the sol-gel polymerization technique. Fe/Si atomic ratios were 6:94, 18:82 and 30:70. Then Si,Fe x -Mt materials were calcined in air at 400 or 500 °C for the APTES removal. The second approach (Al 13 − x Fe x -Mt materials, x = 1 and 2) was based on the pillaring method using Keggin type mixed Al 13 − x Fe x -polycation (x = 1, 2) and montmorillonite from Cheto, Arizona, USA (Mt) as starting material. The intercalated Al 13 − x Fe x -Mt materials were calcined at 400 or 500 °C. The physicochemical characterization pointed out the effectiveness of the incorporation of Fe and Si into the interlayer space of the clay mineral. The fixation of small amounts of Fe (1.9 wt%) increased the basal space from 9.57 to 13.89 Å, but the further fixation of Fe content slightly decreased the basal space. The specific surface area increased from 80 up to 171 m 2 /g. The oligomeric state of Fe 2 O 3 particles depended on its content; the larger Fe content, the larger particle size of Fe 2 O 3 . Catalytic properties of Si,Fe x -Mt and Al 13 − x Fe x -Mt materials were studied in the cyclocondensation of 1,2-phenylenediamine with acetone to 1,5-benzodiazepine. The yield of 1,5-benzodiazepine was found to rise with increasing of the Fe content in Si,Fe x -Mt. Catalytic performance of Si,Fe x -Mt was lower in comparison with Al 13 − x Fe x -Mt, that is in agreement with the amount of Lewis acid sites. [ABSTRACT FROM AUTHOR]