Display omitted •Wet ball milling of -COK-14 zeolite in presence of a dissolved Al source.•Particle size reduction and framework aluminum introduction result from milling.•Milled and aluminated COK-14 contains Brønsted acid sites.•Milled and aluminated COK-14 loaded with platina is an ideal bifunctional catalyst. The precursor of all-silica COK-14 zeolite (OKO topology) with interrupted framework was subjected to wet ball milling in the presence of aluminum isopropoxide. Alumination and particle size reduction of the zeolite crystals was combined in this way. Wet ball milling resulted in fragmentation of the platelet-shape COK-14 crystals while preserving crystallinity. 27Al NMR spectroscopy of the fully condensed COK-14 zeolite, obtained by calcination of milled -COK-14 precursor, confirmed the incorporation of tetrahedrally coordinated Al atoms in the framework. The creation of Brønsted acid sites was confirmed by pyridine adsorption. Loaded with platinum, the sample showed ideal bifunctional catalytic behavior in hydroisomerization and hydrocracking of n-decane model alkane compound. Aluminum incorporation by milling is an alternative to the atomic layer deposition (ALD) process using trimethylaluminum and to thermal alumination. Wet ball milling in presence of aluminum isopropoxide shows great potential for making siliceous zeolites catalytically active.