Third-order optical nonlinearities of the novel diarylethene-phthalocyanine dyads were measured by femtosecond forward degenerate four-wave mixing (DFWM) technique at 800 nm. They have large and ultrafast third-order optical nonlinear responses, which mainly arise from the distortion of the large pi-conjugated electronic charge distribution in the molecules. The second-order hyperpolarizabilities of the diarylethene-phthalocyanine dyads was measured to be (0.76-1.12) x 10(-30) esu. (c) 2007 Elsevier B.V. All rights reserved.