It is now widely accepted that organic materials might be valuable for use in certain NLO applications [1]. In this connection we report here the crystal structure of 3-(5-bromopyridin-2yl)-1,1-dimethylthiourea (I), which crystallizes in the orthorhombic polar space group Fdd (a = 20.809(1), b = 36.959(2), c = 5.462(4) Å, V = 4200.3(5) Å3). In the crystal, I forms dimers where molecules are linked with each other via N1-H1…N3 hydrogen bonds (Fig. 1): H1…N3 2.39, N1…N3 3.119 Å, N1-H1…N3 150°. Owing to the non-centrosymmetric space group of I, its nonlinear optical response was evaluated in the solid state through the Kurtz-Perry technique. The SHG response for the studied compound is of the same order of magnitude of that of urea.