A method of utilizing a catalytic complex having a transition metal (e.g. nickel, cobalt) ion coordinated to a calixarene ligand in upgrading hydrocarbon feedstocks containing C.sub.20 through C.sub.50 hydrocarbons (e.g. vacuum gas oil) to produce light petroleum products (e.g. medium distillate, naphtha) is specified. A method of using the catalytic complex with a supported co-catalyst to synergistically hydrocrack the feedstocks is also provided.

The present invention relates to ligands based on calixarenes, metal complexes including such ligands and their use as homogeneous or heterogeneous catalysts.