A diarylbutadiyne derivative was synthesized using a few steps and gelified in aromatic solvents. The gel prepared at low concentration is made of micrometers-long nanofibrils as shown by scanning electron microscopy. XRD of the dried gel shows sharp features, revealing a well-organized material. A topochemical reaction was performed on the dried gel, and a polydiacetylene presenting reversible thermochromism properties was obtained.