Cyclodimerisation of butadiene into 1,5-cyclooctadiene can be efficiently performed under fluorous-organic biphasic conditions using Ni(COD)(2) as catalytic precursor and triarylphosphites bearing long perfluorinated alkyl chain separated from the aromatic ring by an ethylene spacer group as ligand. As found earlier under homogeneous conditions, phosphites with ortho substituent are much more active than their para-substituted counterpart and a remarkable enhancement of the activity was found when the reaction was carried out in pure fluorous solvent. Catalyst recovery and reuse were also studied. (C) 2004 Elsevier B.V. All rights reserved.