The insertion of carbodiimides into existing metal-heteroatom bonds is an important preparative route for the synthesis of useful ligand systems such as amidinates and guanidinates. Our interest lies in multiple insertions at one metal center and the mechanisms of insertion and rearrangement. We have synthesized and characterized [Me(2)NC(N(i)Pr)(2)](n)M(NMe(2))(3)(-)(n) (n = 1, 2, 3; M = Al, Ga). We have investigated the mechanism of synthesis and discovered a ligand transfer step that is important for the formation of the final products.