Diarylmaleimide derivatives having an indole ring, N-cyanomethyl-2-[2-methoxy-1- benzothiophen-3-yl]-3-[2-methyl-1-octadecylindol-3-yl] maleimide or N-cyanomethyl-2-[2- ethoxy-1-benzothiophen-3-yl]-3-[2-methyl-1-octadecylindol-3-yl] maleimide, were synthesized in an attempt to shift the photosensitive wavelength longer such that it becomes longer than 450 nm. The derivatives underwent the photocyclization reaction upon ...