Metal-organic frameworks (MOFs) belong to the class of microporous coordination polymers consisting of metal ions and organic linkers with a large surface area and pore volume, thanks to which they find diverse applications, for example in gas adsorption and separation, catalysis, drug delivery, or as heavy metal adsorbents1. Currently, efforts are being made to prepare composite materials containing, in addition to MOFs, another meso/macroporous component such as porous oxides (silica, titania, zirconia) or hierarchically porous carbons, to prepare materials with advanced and unique properties2. Therefore, it is necessary to synthesise MOF materials with small grain sizes, which can be achieved, for example, by mechanochemical grinding and incorporating them into the larger pores of the mentioned meso/macro materials. Our work intended to prepare two MOF materials, HKUST-1 and MOF-76, whose common feature is the same organic component, benzene-1,3,5-tricarboxylic acid (H3BTC), but they differ in the central atom, Cu(II) for HKUST-1 and Gd(III) for MOF-76. The different central atoms and connectivity of the BTC linker caused the different framework shapes and the porosity of materials (e.g. SBET(HKUST-1) = 1500 m2 g–1, SBET(MOF-76) = 700 m2 g–1). The compounds can be prepared in the form of cubic (HKUST-1) and needle-like (MOF-76) crystals. The as-synthesized materials were subsequently ground under different conditions (rpm, time, number and type of balls) in planetary mills. Particle size measurements by DLS and XPCS showed a decrease in particle size from microns to nano, but PXRD showed that the compounds´ frameworks were destroyed under long-time milling