Intercalation of an organic photochromic molecule into layered magnetic systems may provide multifunctional properties such as photomagnetism. To build up a photosensitive multifunctional magnet, an organic-inorganic hybrid system coupled with a photochromic diarylethene anion, 2,2'-dimethyl-3,3'-(perfluorocyclopentene-1,2-diyl)bis(benzo[b]thiophene - 6-sulfonate) (DAE), and cobalt LDHs (layered double hydroxides), Co-4(OH)(7)(DAE)(0.5)center dot 3H(2)O, was synthesized by the anion exchange reaction between Co-2(OH)(3)(CH3COO)center dot H2O and DAE. In the dark and under UV-irradiated (313 nm) conditions, Co-4(OH)(7)(DAE)(0.5)center dot 3H(2)O with open and closed forms of DAE were obtained, respectively. The magnetic susceptibility measurements elucidated ferromagnetic intra- and interlayer interactions and Curie temperatures of T-C = 9 and 20 K for cobalt LDHs with the open and closed forms of DAE, respectively. The enhancement of the Curie temperature from 9 to 20 K by substitution of the open form of DAE with the closed form of DAE as an intercalated molecule is attributed to the delocalization of the pi-electrons in the closed form of DAE, which enhances the interlayer magnetic interaction. The enhancement of the interlayer magnetic interaction induced by the delocalization of pi-electrons in intercalated molecules is strongly supported by the fact that the Curie temperature (26.0 K) of cobalt LDHs with (E, E)-2,4-hexadienedioate having a conjugated pi-electron system is enormously higher than that (7.0 K) of the cobalt LDHs with hexanedioate. By UV irradiation at 313 nm, Co-4(OH)(7)(DAE)(0.5)center dot 3H(2)O shows the photoisomerization of DAE from the open form to the closed one in the solid state, which leads to the enhancement of Curie temperature.