The reaction of RHN(CH 2) 3NHR ( 1a, b) ( a, R=2,6- i Pr 2C 6H 3; b, R=2,6-Me 2C 6H 3) with 2 equiv of BuLi followed by 2 equiv of ClSiMe 3 yields the silylated diamines R(Me 3Si)N(CH 2) 3N(SiMe 3)R ( 3a, b). The reaction of 3a, b with TiCl 4 yields the dichloride complexes [RN(CH 2) 3NR]TiCl 2 ( 4a, b) and two equiv of ClSiMe 3. An X-ray study of 4a (P2 1/n, a=9.771(1) Å, b=14.189(1) Å, c=21.081(2) Å, β=96.27(1)°, V=2905.2(5) Å 3, Z=4, T=25°C, R=0.0701, R w=0.1495) revealed a distorted tetrahedral geometry about titanium with the aryl groups lying perpendicular to the TiN 2-plane. Compounds 4a, b react with 2 equiv of MeMgBr to give the dimethyl derivatives [RN(CH 2) 3NR]TiMe 2 ( 5a, b). An X-ray study of 5b (P2 12 12 1, a=8.0955(10) Å, b=15.288(4) Å, c=16.909(3) Å, V=2092.8(7) Å 3, Z=4, T=23°C, R=0.0759, R w=0.1458) again revealed a distorted tetrahedral geometry about titanium with titanium–methyl bond lengths of 2.100(9) Å and 2.077(9) Å. These titanium dimethyl complexes are active catalysts for the polymerization of 1-hexene, when activated with methylaluminoxane (MAO). Activities up to 350,000 g of poly(1-hexene)/mmol catalyst·h were obtained in neat 1-hexene. These systems actively engage in chain transfer to aluminum. Equimolar amounts of 5a or 5b and B(C 6F 5) 3 catalyze the living aspecific polymerization 1-hexene. Polydispersities ( M w/ M n) as low as 1.05 were measured. Highly active living systems are obtained when 5a is activated with {Ph 3C} +[B(C 6F 5) 4] −. A primary insertion mode (1,2 insertion) has been assigned based on both the initiation of the polymer chain and its purposeful termination with iodine.