Several new group 4 alkyl and aryl compounds have been synthesized that possess ancillary cyclooctatetraene ligands. Most of the complexes isolated are anionic and have stoichiometries of [Li(tmed)(2)][(C8H8)-MRCl2], [Li(tmed)(x)][(C8H8)-MR2Cl], or [Li(tmed)(x)][(C8H8)MR3], where M = Zr or Hf, and R = Me, Ph, p-Tol, or CH(SiMe3)(2). Two neutral 14-electron compounds have also been prepared, (C8H8)M[CH(SiMe3)(2)](2 ), where R = Zr or Hf. The compound (C8H8)Zr[CH(SiMe3)(2)](2) appears to react reversibly with 7 atm of carbon monoxide but does not react with dihydrogen even at 70 atm. IR, H-1 and C-13 NMR data are reported, along with the crystal structures of two of the new compounds. (C) 2020 Published by Elsevier Ltd.