Abstract FT-IR and FT-Raman spectra of ethyl methylketone thiosemicarbazone were recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF/6–31G(d) and B3LYP/6–31G(d) basis sets and are assigned with the aid of MOLEKEL program. The first hyperpolarizability, infrared intensities and Raman activities are also reported. The calculated first hyperpolarizability