With respect to experimental part of this thesis, tow- substituted (symetric and asymetric) and three- substituted thiourea derivetive were synthesized while a one-pot three component reaction in the presence of choline chloride-urea eutectic solvent as a catalyst and in water media as a solvent was carried out.The purified drivetive were synthesised in the optimize amounts of catalyst, temoerature and reaction time. After purification of compound, in order to identify the strructuer, some characterization method, such as FT-IR, 1 H-NMR, 13 C-NMR, GC-MS and melthing point were applied. Of the two sort of amine (aliphatic and aromatic), the yield of reaction using aliphatic one is muse more greater than aromatic amine. Forthermore, synthesis of an special thiourea by another functinoal group contaning –NH 2 such as amino acids, amides and etc, was object of our research, the results showed that thos reactions had no chance to happen under adjusted reaction conditions. Regarding theoritical studies, the nitrile hydrolysis reactio mechanis was studied in the presence of acetaldehyd as an organocatalyst. On that basis, five posible routes were designed. Afterward, compound`s energy and frequensy in each pathway were calculated through the Gaussian 09 software.Finelly the desired routes were compared to one another to determine the appropriate rouat in terms of having lower barrier energy and Gi free energy. In order optinize the structuer and calculate the frequency at each route by the ?b97xd method and 6-311++g(2d,2p) basis set was applid. Since the high level accuracy in calculation of transition state is required, the QST3 technique was used in the computation.