Dipyrrole-Fused Naphthalene Diimide as a Building Block for High-Performance Organic Semiconductors

Core annulation of naphthalene diimide (NDI) represents a powerful strategy to modulate its electronic structure and solid-state organization. Here, we report the first pyrrole-fused NDI (NDPI) framework and elucidate its structural and electronic characteristics. Single-crystal X-ray diffraction reveals a highly planar π-core with short π-π stacking distance (3.33 Å) and strong intermolecular N-H···O hydrogen bonding (2.07 Å), highlighting the unique supramolecular features introduced by pyrrole annulation. Building on this motif, a series of donor-acceptor polymers was synthesized and systematically evaluated in OFET devices. The polymers exhibit optical bandgaps of 1.32-1.39 eV. Device mobilities range from 0.10 to 0.59 cm2 V-1 s-1, with charge transport behavior tunable from balanced ambipolar to unipolar n-type depending on donor strength. Correlation of AFM and GIWAXS analyses suggests that charge mobility is governed not solely by crystallinity, but by the interplay between π-π stacking and domain connectivity. This work establishes NDPI as a versatile building block for high-performance organic semiconductors.