1 : 1 Adducts of the copper(I) halides, CuX (X=CI, Br, I), with 2-aminoquinoline (amq) have been synthesized by the crystallization of stoichiometric mixtures of these components from acetonitrile solution, and their structures determined by single-crystal X-ray methods; they are found to span a diverse array of structural types. The chloride crystallizes as a 'stair polymer' array [monoclinic, P21, a 7.487(6), b 3.771(7), c 15.506(2) Š, 95.07(4)ꬠZ= 2]. The bromide is a centrosymmetric dimer , solvated by acetonitrile, [( amq )( MeCN )CuBr2Cu( MeCN )( amq )] [triclinic, PI, a 17.325(8), b 10.376(3), c 7.204(9) Ŭ a 70.36(6), ߠ88.13(7), ? 77.52(3) ꬠZ= 2 dimers]; Cu-Br range from 2.551(2)-2.668(2); Cu-N( amq ) are 2.021(8), 2.010(6); Cu-N( MeCN ) are 1.986(8), 1.960(7) A (two independent dimers ). The iodide alone forms the expected single-strand 'split-stair' polymer [monoclinic, P21, a 12.090(5), b 9.971(5), c 4.132(2) Š, P 98. 50(3) ꬠZ = 21, Cu-I, 2.527(3), 2. 567(3); Cu-N, 2.02(2) Š. Residuals were 0.035, 0.050, 0.045 for 552, 2974, 608 independent 'observed' reflections respectively.