Three compounds were obtained from the reactions of Co(NCS)(2) with pyrazine and 4,4’-bipyridine in different solvents : Co(NCS)(2)(pyz)(2) (1) has a 2D sheet structure, monoclinic, C2/m, a = 10.039(2) Angstrom, b = 10.382(2) Angstrom, c = 7.190(1) Angstrom, beta = 118.64(1)degrees, Z = 2; Co(NCS)(2)(H2O)(2) .(4,4’-bipy) 4,4’-bipy (2) has linear Co-bipy-Co chains connected by hydrogen bonds between H2O and noncoordinated 4,4’-bipy molecules to form stair type sheets, triclinic, , alpha = 7.450(1) Angstrom, beta = 9.020(1) Angstrom, c 10.122(1) Angstrom, a 107.74(1)degrees, P = 104.02(1)degrees, gamma 97.16(1)degrees, Z = 1; Co(NCS)(2)(4,4’-bipy)(2) .(2)(CH3CH2)(2)O (3) has ether molecules intercalated between layers formed by Co(NCS)2 and coordinated 4,4’-bipyridine ligands, monoclinic, P2/c, a 11.483(2)Angstrom, b = 11.397(3)Angstrom, c 13.609(1) Angstrom, beta = 107.55(1)degrees, Z = 2. Compounds 2 and 3 thermally decompose to form the same products. The identities of the decomposition products are discussed.