Frontispiece.

The frontispiece shows a representative π-conjugated aryl-acetylene system and the key design rules in the fine tuning of the chemical/physical properties of such a structure. Appropriate molecular design and the availability of efficient synthetic protocols have led to impressive results in the creation of various high-performance aryl-acetylene semiconductors for organic field-effect transistor/organic photovoltaic cell devices. The major advances in this field are highlighted in the Minireview by Assunta Marrocchi et al. on page 486 ff.