With their versatile absorption, fluorescence, n-type semiconducting and (photo-)stability properties, perylene bisimides have evolved as the most investigated compounds among polycyclic aromatic hydrocarbons during the last decade. In this review we collect the results from about 200 original publications, reporting a plethora of new perylene bisimide derivatives whose properties widely enrich the possibility for the application of these dyes beyond traditional fields. While some applications are highlighted, different from other recent reviews, our focus here is on the advances in the synthetic methodologies that have afforded new bay functionalizations, recently addressed functionalizations at the ortho-positions to the carbonyl groups, and annulation of carbo- and heterocyclic units. An impressive number of perylene bisimide oligomers are highlighted as well which are connected by single bonds or spiro linkage or in a fused manner, leading to arrays with fascinating optical and electronic properties.

This highlight article gives an overview of the development of rylene diimide-based organic field-effect transistors and solar cells.

Two types of helically chiral compounds bearing one and two boron atoms were synthesized by a modular approach. Formation of the helical scaffolds was executed by the introduction of boron to flexible biaryl and triaryl derived from small achiral building blocks. All‐ortho‐fused azabora[7]helicenes feature exceptional configurational stability, blue or green fluorescence with quantum yields (Φ_fl) of 18–24 % in solution, green or yellow solid‐state emission (Φ_flup to 23 %), and strong chiroptical response with large dissymmetry factors of up to 1.12×10⁻². Azabora[9]helicenes consisting of angularly and linearly fused rings are blue emitters exhibitingΦ_flof up to 47 % in CH₂Cl₂and 25 % in the solid state. As revealed by the DFT calculations, their P–M interconversion pathway is more complex than that ofH1. Single‐crystal X‐ray analysis shows clear differences in the packing arrangement of methyl and phenyl derivatives. These molecules are proposed as primary structures of extended helices.

Increased interest in chiral functional dyes has stimulated activity in the field of boron-containing helicenes over the past few years. Despite the fact that the introduction of boron endows π-conjugated scaffolds with attractive electronic and optical properties, boron helicenes have long remained underdeveloped compared to other helicenes containing main group elements. The main reason was the lack of reliable synthetic protocols to access these scaffolds. The construction of boron helicenes proceeds against steric strain, and thus the methods developed for planar systems have sometimes proven ineffective in their synthesis. Recent advances in the general boron chemistry and the synthesis of strained derivatives have opened the way to a wide variety of boron-containing helicenes. Although the number of helically chiral derivatives is still limited, these compounds are currently at the forefront of emissive materials for circularly-polarized organic light-emitting diodes (CP-OLEDs). Yet the design of good emitters is not a trivial task. In this perspective, we discuss a number of requirements that must be met to provide an excellent emissive material. These include chemical and configurational stability, emission quantum yields, luminescence dissymmetry factors, and color purity. Understanding of these parameters and some structure–property relationships should aid in the rational design of superior boron helicenes. We also present the main achievements in their synthesis and point out niches in this area, e.g. stereoselective synthesis, necessary to accelerate the development of this fascinating class of compounds and to realize their potential in OLED devices and in other fields.