A suitable single crystal of (E)-2-Acetyl-4-(4-nitrophenyldiazerwl) phenol, formulated as C14H11N3O4, (I), reveals that the structure is adopted to its E configuration and molecules are linked by C-H center dot center dot center dot O hydrogen bonds. The title compound which has been characterized by IR, UV and single crystal X-ray diffraction analysis at 150K crystallizes in the monoclinic space group C 2/c with a= 12.8640(8) angstrom, b = 7.3264(3) angstrom, c = 26.9330(17) angstrom, alpha = 90 degrees, beta = 93.052(5)degrees, gamma = 90 degrees, Z = 7. The molecular structure and geometry have also been optimized using B3LYP density functional theory method employing the 6-31G (d, p) basis set. To acquire lowest- energy molecular conformation of the title molecule, the selected torsion angle is varied every 10 and molecular energy profile is calculated from -180 degrees to +180 degrees. Furthermore, the molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis, nonlinear optical properties (NLO) and thermodynamic properties for the title molecule are also described from the computational process. (c) 2010 Elsevier B.V. All rights reserved.