Non-fullerene acceptors (NFAs) have attracted considerable attention as promising active materials for near-infrared (NIR) organic photodetectors (OPDs) due to their tunable absorption profiles, wavelength-selective photoresponse, and cost-effective processability. However, many state-of-the-art NFAs exhibit insufficient NIR absorption, which limits the spectral coverage and overall detectivity of NFA-based OPDs. In this study, a series of dithienopyrrole-based NFAs incorporating strongly electron-withdrawing cyano (CN)-substituted end groups were designed and synthesized to extend long-wavelength absorption, precisely tailor energy levels, and promote efficient photo-induced charge transfer. To elucidate structure-property relationships, NFAs with different CN substitution positions were systematically evaluated in terms of their optoelectronic characteristics. The results establish practical design rules for CN-end engineering for developing high-performance NIR OPDs.