Abstract: A novel process for the isomerization of olefins which employs a photocatalytic mixed metal cluster, wherein a solution of the olefin and the cluster is irradiated causing the cluster to become catalytically active and to isomerize the olefin. The photocatalytic mixed metal cluster has the empirical formula:(C.sub.n R.sub.n ').sub.a Fe.sub.b M.sub.c (CO).sub.d L.sub.ewherein n is five; wherein R' is selected from the group consisting of hydrogen, methyl, ethyl, acetyl, formyl, bromine, chlorine and fluorine; wherein M is a transition metal other than iron selected from the group consisting of Mo, Ru, Rh, Sc, Ti, V, Cr, Mn, Co, Ni, Cu and Zn; wherein L is a Group V type ligand; and further wherein a is from about one to five, b and c are from about one to five and b plus c is between two and six, d is from about five to 18 with the proviso that d is always equal to or greater than b plus c, and e is from about 0 to 18.