<p>The scalable fabrication of stretchable conjugated polymer films <i>via</i> solution printing is essential for their practical application in large-area wearable electronics. However, the printed conjugated polymer films typically exhibit high crystallinity, limiting their mechanical deformability. Herein, we propose a plasticizer-assisted printing strategy to simultaneously enhance the stretchability and electrical performance of films based on the conjugated polymer poly(3-(5-(5-methylselenophen-2-yl)thiophen-2-yl)-6-(5-methylthiophen-2-yl)-2,5-bis(4-octyltetradecyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione) (P(TDPP-Se)). The incorporation of a plasticizer trioctyl trimellitate (TOTM) promotes P(TDPP-Se) aggregation in initial solution, facilitates chain alignment under flow field, and shorten solidification process, thereby restricting randomly polymer crystallization. Consequently, a low-crystallinity film with favorable edge-on orientation, strong chain alignment and improved chain dynamics is realized, which effectively alleviates crystallites fragmentation and crack propagation under large strain. The TOTM-plasticized film exhibits approximately 2-fold improvements in fracture strain and charge mobility, along with superior mobility retention under 100% strain in comparison to the neat film. This study provides a feasible approach for microstructure control in printed stretchable conjugated polymer film.</p>