A monoazo disperse dye (DMA) was prepared by diazotizing 4-aminoacetophenone and coupling with N, N-dimetylaniline. It was fully characterized by IR, UV, H-1-NMR, C-13-NMR, TGA, and mass spectral techniques as well as X-ray crystallographic methods. The electronic absorption spectra of the dye in solvents of different polarities covers a lambda(max) range of 437-460 nm. It is shown that the compound exhibits positive solvatochromism in solution. In addition, the absorption properties of the compound change drastically upon acidification, as the protonation of beta-nitrogen atom of the azo group increases the donor-acceptor interplay of the pi system. The molecular structure, spectroscopic and nonlinear optical (NLO) properties of DMA were also investigated theoretically by performing Density Functional Theory (DFT) and Hartree-Fock (HF) levels of theory using the 6-31+ G(d, p) basis set. The optimized geometries, electronic absorption spectra calculated using time-dependent DFT (TD-DFT) method and NMR spectra were evaluated via comparison with experimental values. In addition, thermal analysis shows that DMA is thermally stable up to 258 degrees C.