A multijunction solar cell assembly and its method of manufacture including first and second discrete semiconductor body subassemblies, each semiconductor body subassembly including first, second and third lattice matched subcells; a graded interlayer adjacent to the third solar subcell and functioning as a lateral conduction layer; and a fourth solar subcell adjacent to said graded interlayer being lattice mismatched with respect to the third solar subcell; wherein the average band gap of all four cells is greater than 1.44 eV.