The synthesis of 4-phenyl-6-(4´bromophenyl)[2,1-b]imidazothiazol (II) from 2-amino-4-phenylthiazol (I) is reported in the present paper. Both compounds were investigated using NMR and IR techniques, as well as x-ray powder diffraction. IR spectral data of compound I show N-H stretching and bending frequencies of the NH2 group (3440 and 3260 cm-1), the aromatic overtone indicating monosubstituted phenyl ring (1605 and 770 cm-1), and the C=N and C-N frequencies of thiazolic ring (1530 and 1280 cm-1). IR spectral data of compound II exhibit characteristic bands (Csp2-H and C=N sym. y asym.) as reported in previous references. 1H-NMR signals of compound I show the thiazolic group proton (7.80 ppm) and those corresponding to compound II characteristic chemical shifts of H2',6' (7.62 ppm) and H3',5' (7.90 ppm) protons of the phenylic group bonded at position 2 of the imidazole ring. 13C-NMR spectral data of the compound II show characteristic C9a, C4a and C8a signals of the imidazole group (174.1, 166.9 and 121.1 ppm) as well as carbon signals of the phenyl group. X-ray diffraction patterns exhibit sharp intensity maxima, which result from the high crystallinity of the two solid phases (low background and no amorphous zone). All patterns were indexed. The cell parameters were determined and refined. Crystals of compound I are tetragonal, a = 12.143 (1), c = 5.771 (2) Å, space group P4/mmm; Crystals of compound II are orthorhombic, a = 12.183 (4), b = 12.150 (10), c = 5.769 (2) Å, space group Pmmm. The structures of these compounds agree with their IR, 1H-NMR and x-ray diffraction spectra.