In this paper we study structure stability of sulfur derivative of pyrazine using combination of DFT/B3LYP method and 6-311G (d, p) basis set. To know transition spectra from ground level and other higher energy level we also studied TDDFT of title molecule and calculated UV spectrum is compared with experimental spectra of pyrazine available on NIST book. Calculated IR after scaling also compared with experimental spectra of pyrazine available on NIST book to know performance of DFT/B3LYP method. To know chemical activity we study electronic parameter like HOMO-LUMO etc. The main aim of this paper to calculate several biological parameter and DOCKING with appropriate protein suggested by Swiss dock online server. In this study we find that sulfur increase toxicity as well as biological activity of title compound as compared to pyrazine.