The combination of two second-order nonlinear optical (NLO) processes, termed cascading, can induce third-order nonlinearities, which are of major interest for all-optical signal processing. The concept of cascading and the basic ideas behind it are explained and some of the molecules of greatest potential in this area (e.g., DANPH, see Figure) introduced. Methods for determining cascaded nonlinearities, effects based on cascaded processes, and materials considerations are also reviewed.