[Cp' 2 ZrCl(PHTipp)] (1) (Cp'=η 5 -C 5 H 4 Me, Tipp=2,4,6-Pr i 3 C 6 H 2 ) and [Cp o 2 ZrCl(PHCy)] (2) (Cp o =η 5 -C 5 EtMe 4 , Cy=cyclohexyl) readily insert CyNC to give [Cp' 2 ZrCl{η 2 -NCyC(PHTipp)}] (3) and [Cp o 2 ZrCl{η 2 -NCyC(PHCy)}] (4). 3 and 4 were characterised spectroscopically (IR, NMR, MS) and by crystal structure determination, which showed an η 2 bonding mode (C,N) of the NCyC(PHR) ligands. Of the two possible coordination modes of the ligand, 3 is obtained exclusively as the exo isomer, in which the NCy group is adjacent to the Zr Cl bond, while for 4, both isomers (exo and endo) are formed [1:1.5 (4a:4b)], whereby the endo isomer is favoured. The exo isomer 4a was structurally characterised.