Chloro and azido germanium(II) and tin(II) 1,5-diazapentadienyl complexes have been investigated. The treatment of GeCl2. (1,4-dioxane) or SnCl2 with [(Mes)(2)DAP]Li in a 1:1 molar ratio gave the corresponding germanium(II) or tin(II) chloro complexes [(Mes)(2)DAP]MCl (where [(Mes)(2)DAP] =2,4-dimethyl-N,N'-bis(2,4,6-trimethylphenyl)1,5-diazapentadienyl; M = Ge or Sn). [(Mes)(2)DAP]GeCl and [(Mes)(2)DAP]SnCl are monomeric in the solid state. The C3N2M rings adopt a flattened boat conformation. The metathesis reaction between [(Mes)(2)DAP]MCl and sodium azide affords the azido compounds [(Mes)(2)DAP]MN3 in excellent yield. X-ray analysis revealed that [(Mes)(2)DAP]GeN3 features an essentially linear azide moiety and a nearly planar heterocyclic C3N2Ge ring system. The azide group occupies a site above the C3N2Ge ring. The solid-state structure of the tin azide [(Mes)(2)DAP]-SnN3 shows weak intermolecular Sn . . .N contacts. It features a linear azide moiety and a planar heterocyclic C3N2Sn ring system. Both azides have long (M)N-N(N) bonds and short (MN)N-N bonds. IR spectra of [(Mes)(2)DAP]GeN3 and [(Mes)(2)DAP]SnN3 display nu (asym)(N-3) bands at 2062 and 2060 cm(-1), respectively. N-14 NMR spectroscopic data show three well-separated signals for the nitrogen atoms of the azide moieties. Structural and spectroscopic data suggest the presence of very similar azide groups in the Ge(II) and Sn(II) adducts. The dominant canonical form of the metal-azide moiety is M-N-N equivalent toN.