Described herein is a catalyst precursor composition comprising at least one metal from Group 6 of the Periodic Table of the Elements, at least one metal from Groups 8-10 of the Periodic Table of the Elements, and a reaction product formed from (i) a first organic compound containing at least one amine group and at least 10 carbon atoms or (ii) a second organic compound containing at least one carboxylic acid group and at least 10 carbon atoms, but not both, wherein the reaction product contains additional unsaturated carbon atoms, relative to the first or second organic compound, wherein the metals of the catalyst precursor composition are arranged in a crystal lattice, and wherein the reaction product is not located within the crystal lattice. A process for preparing the catalyst precursor composition is also described, as is sulfiding the catalyst precursor composition to form a hydroprocessing catalyst.