Abstract Chiral optoelectronic materials capable of interacting with circularly polarized (CP) light have emerged as promising candidates for next‐generation technologies. This study presents a facile strategy for the preparation of chiroptical films by blending an achiral conjugated polymer, PDVT‐10, containing diketopyrrolopyrrole (DPP) moieties with chiral small molecules, 1,1′‐binaphthyl‐2,2′‐diamine (BN). Chirality induction in conjugated polymer systems is driven comprehensively from intermolecular hydrogen bonding to co‐crystallization with aggregation, as revealed by a stepwise approach of optical and X‐ray scattering analyses depending on the ratio. By optimizing the blending ratio of PDVT‐10 and BN to 7:3, near‐infrared (NIR)‐circularly polarized light‐sensitive phototransistors are successfully fabricated on 850 nm, which exhibit distinct CP light discrimination and photodetection performance. These findings provide insights into the mechanism of inducing chirality to achiral conjugated polymers, enhancing chiroptical properties, and providing applications in CP photosensitive optoelectronics.