The crystals of the title compound (C19H15Cl2CuN5O) are orthorhombic, space groupPbca; the unit cell dimensions area= 14.802 (3),b= 16.447 (4),c= 15.654 (4) Å;Z= 8. The structure has been determined from diffractometer data by Patterson and Fourier methods and refined by block‐diagonal least‐squares calculations toR= 4.3% for 2648 independent reflexions. The copper atom is five‐coordinated through two chlorine atoms (Cu‐Cl = 2.258, 2.500 Å) and three nitrogen atoms (Cu‐N = 2.039, 2.053, 2.058 Å) from the organic molecule which behaves as a tridentate ligand. The heteroatomic ring of the quinazoline system shows a half‐chair conformation, as a consequence of the imperfect hybridization of N(3) and N(4) and of the tetrahedral char