The crystal structures of the title compounds, Cu(SCN)L, L = 2-methylpyridme (l),2 ,6-dimethylpyridine (2), and Cu(SCN)b, L = 2-, 3-, and 4-methylpyridine (3-5, respectively), 2,4-dimethylpyridine (6), quinoline (7), have been established by single-crystal X-ray diffraction at 295 K and refined by full-matrix least squares to residuals of 0.026,0.039,0.048,0.032, 0.054,0.058, and 0.029 for 1164, 1339, 1499, 1731, 903, 1748 and 468 independent "observed" reflections, respectively. Crystals of 1 are triclinic, PI, with a = 9.452 (3) A, b = 8.077 (3) A, c = 5.779 (1) A, a = 104.33 (2)O, @ = 96.64 (2)O, y = 100.83 (3)O, and 2 = 2; the structure is a polymer consisting of pairs of CuL(SCN)CuL(SCN) strands linked by centrosymmetric four-membered Cu2S2a nd eight-membered CU(SCN)~CrUin gs. Crystals of 2 are monoclinic, P2,/c, with a = 7.721 (2) A, b = 7.753 (2) A, c = 16.1 13 (4) A, @ = 90.67 (2)O, and 2 = 4; the structure is a single-stranded polymer-CuL(SCN)CuL(SCN). Crystals of 3 are orthorhombic, Fdd2, with a = 43.68 (1) A, b = 16.402 (4) A, c = 8.064 (3) A, and 2 = 16. Crystals of 4 are monoclinic, P2]/n, with a = 17.68 (1) A, b = 5.874 (4) A, c = 14.367 (8) A, @ = 112.91 (4)O, and 2 = 4. Crystals of 5 are monoclinic, El, with a = 14.59 (2) A, b = 5.823 (6) A, c = 8.953 (10) A, @ = 106.44 (lo)', and 2 = 2. Crystals of 6 are monoclinic, P21/c, with a = 28.93 (3) A, b = 5.867 (4) A, c = 20.19 (3) A, @ = 112.70 ( 8 ) O , and 2 = 8. Crystals of 7 are orthorhombic,P 212121wr ith a = 16.219 (4) A, b = 12.838 (3) A, c = 8.032 (2) A, and 2 = 4. In spite of the diverse crystal symmetries found for 3-7, all contain single-stranded CuL2(SCN)CuLz(SCN)CuLpzo lymers, with different conformational types. All complexes were synthesized by reaction of copper(1) thiocyanate with the parent base, with or without the presence of acetonitrile as solvent.