Abstract: Photochemical reaction of ferrocene-tetracyanoethylene (Fc-TCNE) complexes has been investigated. The photochemistry of (Fc-TCNE) in the solid-state is. distinct from that in solution. While only cyanoferrocene (F₁) was obtained when the reaction was carried out in solution, both cyanoferrocene (F₁) and 1,2-diferrocenyl-1,1,2,2-tetracyanoethane (F₂) were obtained when it was carried out in the solid-state.