The crystal structure of the title compound, 2-(4-amino-3-benzyl-2-thioxo-2,3-dihydrothiazol-5-yl)benzoxazole, was determined. The crystal has P1 space group and triclinic system with unit cell parameters a = 5.174(3)？？, b = 6.411(6)？？, c = 12.369(10)？？, α = 86.021(4)°, β = 84.384(5)°, and γ = 77.191(5)°. The structure consists of benzoxazole group connected with benzyl via thiazole (attached with amino and thione). Benzoxazole and thiazole rings are almost planar (maximum deviation at C1, ？0.013(3)？？, and C10, 0.0041(3)？？, resp.). The phenyl ring is nearly perpendicular to both thiazole and benzoxazole rings. A network of intermolecular hydrogen bonds and intermolecular interactions stabilizes the structure, forming parallel layers. The molecular geometry obtained using single crystal analysis is discussed along with results of the molecular mechanics modeling (MM), and the results showed the same cis conformation between benzoxazole nitrogen atom and the amino group. 1. Introduction Organic compounds natural or synthetic are the main source of medical agents and drugs, so knowledge of their molecular structure and conformation is important because it has a direct correlation with their activity. Among of bioactive organic compounds are benzoxazole derivatives; previous reports revealed that substituted benzoxazoles possess diverse chemotherapeutic activities including antibiotic, antimicrobial, antiviral, topoisomerase inhibitors, and antitumor activities [1–3]. Benzoxazoles possess the structural isosteres of natural nucleotides (such as adenine and guanine) which allow them to interact easily with the biopolymers of living systems and different kinds of biological activity can be obtained [4]. Benzoxazoles are widely used in industry, among them 2-phenylbenzoxazoles used as organic brightening laser dyes. Other industrial applications were reported, such as dopants in organic light-emitting diodes, chromophores, and chemosensors [5, 6]. Molecular mechanics calculations are an efficient tool and an important aspect of molecular modeling, used for predicting structure and energy of molecules and heats of formation and used to compare different conformations of the same molecule, further reading in [7, 8]. As reported previously, knowing the structure and conformation of 2-substituted benzoxazole derivatives gives important information for predicting their mode of orientation on the receptor [1]. So, more bioactive drugs in the pharmaceutical industry can be designed. As a result this provides the pharmaceutical community with useful information which
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