Inorganic/organic hybrid films were fabricated from (ferrocenylmethyl)dimethyl(w-trimethoxysilyl)alkylammonium hexafluorophosphate (FDAH-C3; FDAH-C11) and characterized using cyclic voltammetry and potential step chronocoulometry. The materials were prepared via the acid catalyzed hydrolysis and co-condensation of FDAH with tetramethoxysilane (TMOS) in fixed mole ratios of 1:50, 1:25, 1:10 FDAH/TMOS. Gel-immobilized ferrocene was found to be stable, electroactive, and functional. The shapes of the voltammetric curves depended strongly on the amount of FDAH in the film, the length of the alkyl spacer in the FDAH modifier, and the supporting electrolyte anion. The voltammetric results suggest that the FDAH/TMOS hybrid films are poorly solvated and inhomogeneous. The apparent diffusion coefficients for gel-immobilized ferrocene were measured in 0.1 M KClO4 using chronocoulometry and found to be similar to 10(-9)-10(-10) cm(2) s(-1). The FDAH-C3 \TMOS (1:50) hybrid films have been applied in the catalytic oxidation of catechol to evaluate their usefulness in electrocatalysis applications. At slow sweep rates, significant catalytic current can be observed for catechol at the FDAH-modified electrode whereas little can be observed for a much larger catechol derivative, catechol violet.