Reaction of 2 equiv of lithium dicyclohexylformamidinate with SnCl4 afforded the new species Sn(CyNC(H)NCy)(2)Cl-2 (Cy=cyclohexyl) (1). Addition of MeLi and (t)BuLi to CyN=C=NCy and Me(3)SiN=C=CSiMe(3), respectively, provided an entry to the high-yield syntheses of Sn(CyNC(Me)NCy)(2)Cl-2 (2) and Sn(Me(3)SiNC(CMe(3))NSiMe(3))(2)-Cl-2 (3). Spectroscopic and elemental analysis confirmed the formulas of these new species. Compounds 1 and 3 were further characterized by X-ray crystallography and shown to possess distorted octahedral coordination geometries of the metal center with the cis-dichloride groups. The structural determination of 3 represents the first structural confirmation of the new bulky amidinate ligand (Me(3)SiNC(CMe(3))NSiMe(3))(-). Comparison of the solution structures of 1-3 was provided by NMR spectroscopy, which showed that while 1 was fluxional at room temperature, 2 and 3 exhibited restricted fluxionality. Differences in the solid state structures of 1 and 3 were attributed to the steric interactions within the ligands. Crystal data for 1 : orthorhombic, Pnca, a=17.553(5) Angstrom, b=20.275(9) Angstrom, c=9.757(6) Angstrom; empirical formula SnCl2N4C26H46(toluene), R(F) 0.044, R(W) 0.051. Crystal data for 3 : monoclinic P21/n, a=13.515(8) Angstrom, b=16.179(8) Angstrom, c=15.974(4) Angstrom, beta=97.69(6)degrees, empirical formula SnCl2Si4N4C22H54, R(F) 0.032, R(W) 0.045.