Organic semiconductor (OSC) photocatalysts are promising due to tunable band gaps and energy levels. However, traditional OSCs suffer from high exciton binding energy, short exciton diffusion lengths (EDL), and low ambipolar charge mobility, limiting their performance. Recent focus on nanoparticles (NPs) with internal heterojunctions improves charge separation but poses challenges in maintaining size and composition homogeneity. This study introduces a novel approach using "dark excitonic" single-component organic NPs that are capable of bypassing the conventional exciton dissociation pathways. Additionally, the short EDL is found to be derived from a high polaron yield, promoting the efficient generation of long-lived charges. The poor mobility issue is tackled by introducing low-level doping of the second component. Hence, high charge generation and hydrogen evaluation are possible with a single component removing difficulty in maintaining homogeneity in composition and morphology.