Four new complexes [{Ln[[graphic omitted]CH(CH₂C₅H₄)]Cl}₂](Ln = Y, Yb, Sm or Nd) were synthesised by using furan-bridged bis(cyclopentadienes) as ancillary ligands and characterized by elemental analyses, mass, IR and ¹H NMR spectroscopy. The spectra indicate that these complexes are chloride-bridged dimers and the two furan-bridged cyclopentadienyl rings co-ordinate to each metal in a chelating fashion with in transolecular co-ordination between the oxygen atom and the metal. The effects of the bridging chain and the central metal upon the reactivity of organolanthanide hydrides generated in situfrom the [Ln(C₅H₅)₂Cl]–NaH system were investigated. The reactivity can be tuned not only by varying the ligands but also by taking advantage of the lanthanide contraction. The ligand tunability varies for different reactions. More reactive organolanthanide hydride species (in situ) can be obtained by both ‘ligand tuning’ and ‘metal tuning’, i.e. by selecting the appropriate ancillary ligands and the early lanthanide metals.