The idea of rational design of electronic properties of materials via manipulation of a molecular structure is a centerpiece of organic electronics. Indeed, a range of organic materials with metallic, semi- and superconducting, magnetic, non-linear optical and lasing properties have been reported. However, an optimization of these properties and realization of high-performance organic optoelectronic devices is still largely an empirical exercise. The “rational design” approach is severely limited by our inability to control a supramolecular structure and the resulting “solid state” properties that emerges, is a fundamental challenge of the field.

Through analysis of our own failures and successes in design of organic semiconductors, I will discuss how supramolecular organization overwhelmingly controls optical and electronic properties of these materials, and propose solutions towards their rational design. Specific examples will include (i) materials for light-emitting transistors; (ii) a complementary H bonding in multichannel semiconductors; (iii) deciphering supramolecular structure of semiconductor interfaces using Scanning Tunneling Microscopy and (iv) an on-surface epitaxial synthesis of two-dimensional conjugated polymers (“organic graphenes”).