p-Methylphenylthiourea (I) is monoclinic, space group P21/n, with a 0.5618(1), b 0.8487(4), c 1.7865(3) nm, and b 93.53 (1)? Z = 4, dc = 1.298. The final R = 0.0396 and Rw = 0.0564. p-Bromophenylthiourea (II) is monoclinic, space group P21/n, with a 0.9096(6), b 0.8991(4), c 1.0659(8) nm, and b 105.59(6)? Z = 4, dc = 1.836. The final R = 0.073 and Rw = 0.0560. The thiourea moieties in I and II formed by the atoms S(1), C(1), N(1) and N(2) are planar. Dihedral angle between this plane and benzene ring are 63.5?for I and 68.5?for II. The quantum chem. calculation of I was undertaken, and the results are compatible with those of the crystal structure determination Atomic coordinates are given.

Key words: PHENYL GROUP, CRYSTAL STRUCTURE DETERMINATION, CALCULATION, THIOUREAS, BOND LENGTH, BOND ANGLE, BROMINE COMPOUNDS, QUANTUM CHEMISTRY, CNDO APPROXIMATION, ELECTRONIC STRUCTURE