The organobismuth(III) and dibismuthine complexes bearing N,N'-disubstituted 1,8-diaminonaphthalene ligand were prepared. The reaction of LBiNMe2 (1) [L = 1,8-(NSiMe3)(2)C10H6] with ClSiMe3 results in the elimination of Me3SiNMe2, while PhCCH, Cp*H, and PhOH proceed via HNMe2 elimination and provide the complexes of LBiCl (2), LBiCCPh (3), LBiCp*(4), and LBiOPh (5), respectively. Reaction of 1 with AlMe3 in n-hexane yields LBiMe (6). Compound 1 reacts with diisopropylcarbodiimide and phenyl isocyanate under insertion at the Bi-NMe2 bond to give the addition products LBi(NiPr)(2)CNMe2 (7) and LBiN(Ph)C(O)NMe2 (8). The reactions of 1 with sulfur and PhSiH3 result in the formation of LBi-S-BiL (9) and LBi-BiL (10), respectively. Compounds 2-10 were characterized by elemental analysis, H-1, C-13, and Si-29 NMR spectroscopy, and X-ray crystallographic studies.