The metal β-diketiminato ligand-to-metal binding modes are briefly reviewed, with reference particularly to our previous work on metal complexes using the ligands [{N(R 1 )C(R 2 )} 2 CH] (R 1 =SiMe 3 =R and R 2 =Ph; or R 1 =C 6 H 3 Pr i 2 -2,6 and R 2 =Me). The syntheses of the β-diketimines H[{N(R)C(Ar)} 2 CH] 1 (Ar=Ph) and 2 (Ar=C 6 H 4 Me-4) and the ansa-CH 2 -bridged bis(β-diketimine)s 3 (Ar=Ph) and 4 (Ar=C 6 H 4 Me-4) are reported. Thus, from the appropriate compound Li[{N(R)C(Ar)} 2 CH] and H 2 O, (CH 2 Br) 2 or CH 2 Br 2 the product was 2, 3 or 4. Compound 1 was prepared from K[{N(R)C(Ph)} 2 CH] and (CH 2 Br) 2 . Each of 3 or 4 with LiBu n surprisingly yielded the bicyclic dilithium compound 5 (Ar=Ph) or 6 (Ar=C 6 H 4 Me-4) in which each of the β-diketiminato fragments is an N,N′-bridge between the two lithium atoms and the CH 2 moiety joins the two ligands through their central carbon atoms. However, 4 with AlMe 3 yielded the expected ansa-CH 2 -bridged-bis[(β-diketiminato)(dimethyl)alane] 7, which was also obtained from 6 and Al(Cl)Me 2 . X-ray structures of the known compounds 2 and 3, and of 5, 6 and 7 are presented; the 1 H NMR spectra of 6 in toluene-d 8 show that there is restricted rotation about the NC–C 6 H 4 Me-4 bond.