Unsubstituted acenes are intriguing from both experimental and theoretical point of views; however, the preparation and handling of such acenes have been difficult due to their low solubility and high reactivity. Here, unsubstituted nonacene was successfully synthesized in preparative scale.

The development of photoresponsive systems that show multiple-state photochromism has remained a challenging task. We present an alkynylgold(I) complex that features multiple photoinduced color changes, in which the gold(I) center plays an important role in allowing multiple photochromic reactions.