The invention provides a two-step process for converting cyclopentadiene dimer to a high density fuel mixture comprising the steps of:(a) reacting said cyclopentadiene dimer in the presence of a solid catalyst comprising a porous crystalline material having a Constraint Index of from about 0.1 to about 12 under oligomerization/isomerization conditions to convert at least a portion of said cyclopentadiene dimer to a normally liquid intermediate product containing cyclopentadiene trimer, cyclopentadiene tetramer, and the isomerized and oligomerized products derived from the reaction of at least three cyclopentadiene monomer units;(b) hydrogenating said normally liquid intermediate product of step (a) in the presence of a hydrogenation catalyst to form a normally liquid high energy density fuel.