Tuning Conjugation and Charge Transport in Supramolecular Semiconductors via Hydrogen‐Bonding Position

Precise control over conjugation pathways is essential for developing high‐performance organic semiconductors, particularly in hydrogen‐bonded systems where subtle structural variations strongly influence hydrogen bond strength, molecular planarity, supramolecular organization, and charge transport. We demonstrate that the relative positioning of hydrogen‐bonding with respect to a π‐conjugated core enables the modulation of conjugation pathways through controlled intra‐ or intermolecular interactions. A series of diketopyrrolopyrrole small molecules bearing amides at defined distances from the conjugated backbone was designed to selectively favor distinct hydrogen‐bonding types and strengths. Our combined approach, including density functional theory, vibrational and electronic spectroscopies, electrochemistry, and solid‐state characterization, reveals that proximal amide groups favor intramolecular hydrogen‐bonding, disrupting backbone planarity and limiting effective π‐conjugation. In contrast, distal amides promote intermolecular hydrogen‐bonding, sometimes involving DPP carbonyl groups, leading to extended conjugation pathways and enhanced supramolecular organization in the solid state. This modulation of hydrogen‐bond topology and strength results in markedly different charge‐carrier dynamics and transport, evidenced by electrodeless photoconductivity measurements and organic field‐effect transistors. Overall, this work establishes hydrogen‐bond and strength, rather than hydrogen‐bonding alone, as key molecular design parameter to modulate conjugation extension and charge transport in hydrogen‐bonded semiconductors, providing general insights for designing functional supramolecular electronic materials.