Metal organic frameworks (MOFs) are a class of porous polymeric material composed of metal ions or clusters linked together by organic bridging ligands. Their large surface areas accompanied by uniform pores, open metal sites, and diverse available post-synthesis functionalization routes make MOFs promising candidate materials for gas storage, separation, and heterogeneous catalysis. MOFs are typically synthesized by solvothermal reactions in organic solvents or in water, but have also been prepared in ionic liquids (ILs) recently; examples of the latter include Cu-BTC (BTC: 1,3,5-benzenetricarboxylate), Ln-BTC, Cd-BTC, Zn-BTC, and others. ILs have been attracting increasing attention as a solvent of choice for chemical synthesis, because of their unique integration of various properties such as essentially zero vapor pressure, excellent solvating properties, easy recyclability, and high thermal stability. The majority of the reports dealing with MOF synthesis have focused on ILs derived from 1-alkyl-3-methylimidazolium. However, deep eutectic solvents (DESs), mixtures of two or more compounds that have melting points lower than that of either of their constituents, are known to exhibit solvent properties very similar to those of ILs and have been employed for MOF synthesis. They have advantages over other types of ILs such as ease of preparation as pure phases from easily available components, low prices, and relative unreactivity towards atmospheric moisture. DES can act as both a solvent and a ligand during the MOF synthesis. MOFs can be synthesized by sonochemical method which has exhibited rapid synthesis kinetics, uniform particle morphology, and excellent phase purity in inorganic materials synthesis. The sonochemical method promotes homogeneous nucleation and reduces crystallization time considerably via the creation, growth, and collapse of an acoustic cavity, generating extremely high temperature (5000-25000 K)/pressure as well as fast heating and cooling rates. In the sonochemical synthesis route, in connection with this reaction mechanism, DESs are thought to create cavitation easily at relatively high temperatures due to their low vapor pressures, and thus have good potential as a reaction medium in the sonochemical synthesis of nanomaterials. In this work, we have chosen the widely investigated Cu3(BTC)2 as a representative MOF material for sonochemical synthesis using choline chloride/dimethylurea DES as a solvent (designated as S-CuBTC). To the best of our knowledge, this is the first report of sonochemical synthesis of a MOF structure in a DES. Effects of various synthesis parameters on the crystallization process of Cu3(BTC)2 were examined, and the properties of the sample were compared to those of Cu3(BTC)2 prepared via a conventional ionothermal synthesis route in an oven (designated as C-CuBTC). In order to use MOFs for adsorption, rigorous guest removal from the pores has to be performed so as to achieve the highest possible surface area (and pore volume). This is typically accomplished by solvent washing and vacuum treatment. Since the mixture of choline chloride and 1,3dimethylurea in a molar ratio of 1:2 used in this work has a eutectic temperature of around 70 C, removal of the solvent guest before it solidifies inside the pores is challenging. Thus, an effective activation procedure for Cu3(BTC)2 samples obtained under ionothermal synthesis conditions was briefly examined by conducting repeated sample washing with de-ionized water and ethanol in the manner described in entries I to V in Table 1. No apparent PXRD patterns or morphology changes were observed after washing step II (see Figure S1 and S2). The corresponding SEM images after different washing steps did not reveal any noticeable differences either, except that the DES coated at the external surface in the Cu3(BTC)2 sample was removed. However, repeated washing (200 mL × 2) by de-ionized water and ethanol was necessary to obtain the BET surface area of a high quality Cu3(BTC)2, as shown in Table 1. Elemental analysis of the C-CuBTC sample after washing treatment IV confirmed the virtual elimination of DES; The