A family of bandgap-tunable pyrroles structurally related to rylene dyes was computationally designed and prepared using robust, easily scalable chemistry. These pyrroles show highly variable fluorescence properties and can be used as building blocks for the synthesis of electron-deficient oligopyrroles. The latter application is demonstrated through the development of π-extended porphyrins containing naphthalenediamide or naphthalenediimide units. These new macrocycles exhibit simultaneously tunable visible and near-IR absorptions, an ability to accept up to 8 electrons via electrochemical reduction, and high internal molecular free volumes. When chemically reduced under inert conditions, the most electron-deficient of these macrocycles revealed reversible formation of eight charged states, characterized by remarkably red-shifted optical absorptions, extending beyond 2200 nm. Such features make these oligopyrroles of interest as functional chromophores, charge-storage materials, and tectons for crystal engineering.

A hexapyrrolohexaazacoronene derivative containing 37 fused rings, the largest such system to date, was obtained from a naphthalenomonoimide-pyrrole hybrid in a concise and efficient synthesis. This large heterocycle is electron-deficient and shows extended redox activity, spanning at least 13 oxidation levels, but is otherwise chemically stable. Radial expansion of the π system creates a chromophore characterized by strong fluorescence and solvatochromism in the neutral state, and strong near-infrared absorption in the charged states. Additionally, the enlarged and ruffled aromatic surface supports a unique self-assembly mode in the crystal, leading to the formation of highly solvated organic clathrates.

Chiral heteroaromatic propellers based on radially p-extended hexapyrrolohexaazacoronenes were obtained in ac oncise synthesis from suitably functionalizedd onoracceptor monopyrroles.T oo vercome steric hindrance,anew cyclodehydrogenation method was developed, and it uses bromine electrophiles as oxidative coupling agents instead of the commonly employed high-potential oxidants.T he new reaction offers high yields of propeller-shaped targets,even for electron-deficient precursors,a nd shows electrophile-dependent stereoselectivity,w ith N-bromosuccinimide and dibromine yielding,r espectively D 6 -a nd C 2 -symmetric products. The propeller azacoronenes are chiral and can be separated into configurationally stable enantiomers.I na ddition to providing steric bulk, peripheral functionalization considerably affects the electronic properties of the propellers,w hich exhibit reduced optical and electrochemical band gaps,a nd amore clearly defined electroreduction behavior.

Versatile π-aromatic building blocks and selective coupling transformations enable rapid assembly of complex electron-deficient molecules, useful as n-type organic semiconductors.

Pd -mediated annulative double C-H activation is shown to efficiently convert 1,n-dipyrrolylalkanes into extensively π-conjugated bipyrroles not accessible by conventional oxidative coupling protocols. This approach is applicable to both electron-rich and electron-deficient systems, and has been further developed into tandem processes involving further cyclization of substituents or oxygenation of pyrrolic α-positions. The new bipyrrole intermediates show enhanced fluorescence as well as tunable optical properties controlled by the alignment of chromophore subunits. Photophysical data, including femtosecond transient absorptions, reveal solvent-induced intramolecular charge transfer in their excited states, dependent on the polarity of the medium.

Free base, zinc and palladium π‐extended porphyrins containing fused naphthalenediamide units were employed as photosensitizers in antimicrobial photodynamic therapy (aPDT). Their efficacy, assessed by photophysical and in vitro photobiological studies on Gram‐positive bacteria, was found to depend on metal coordination, showing a dramatic enhancement of photosensitizing activity for the palladium complex.

Chiral heteroaromatic propellers based on radially p-extended hexapyrrolohexaazacoronenes were obtained in ac oncise synthesis from suitably functionalizedd onoracceptor monopyrroles.T oo vercome steric hindrance,anew cyclodehydrogenation method was developed, and it uses bromine electrophiles as oxidative coupling agents instead of the commonly employed high-potential oxidants.T he new reaction offers high yields of propeller-shaped targets,even for electron-deficient precursors,a nd shows electrophile-dependent stereoselectivity,w ith N-bromosuccinimide and dibromine yielding,r espectively D 6 -a nd C 2 -symmetric products. The propeller azacoronenes are chiral and can be separated into configurationally stable enantiomers.I na ddition to providing steric bulk, peripheral functionalization considerably affects the electronic properties of the propellers,w hich exhibit reduced optical and electrochemical band gaps,a nd amore clearly defined electroreduction behavior.

Conductive π-conjugated polymers were electrochemically generated from a variety of donor–acceptor pyrroles containing fused perimidine subunits. Alternating oxidative and reductive polarization of these precursors induces multidirectional coupling involving both perimidine and acenaphtho­[1,2-c]­pyrrole moieties, producing cross-linked polymeric structures. Chemical oxidation experiments and computational analyses of spin densities in the charged pyrrole intermediates indicate that the formation of inter-perimidine linkages occurs prior to pyrrole–pyrrole couplings. In the resulting polymers, a very stable dication state is achievable with the positive charge located on the bis-perimidine linker. These polymers do not show any stable neutral state and can be easily reduced. Cationic and anionic states of these electrogenerated films were investigated in the solid state by UV–vis–NIR and EPR spectroelectrochemistry, assisted by DFT calculations.