Long-wavelength afterglow emitters are crucial for optoelectronics and information security; however, it remains a challenge in achieving high luminescence efficiency due to the lack of effective modulation in electronic coupling and nonradiative transitions of singlet/triplet excitons. Here, we demonstrate an organic-carbon-dot (CD) hybrid system that operates via a space-confined energy transfer strategy to obtain bright afterglow emission centered at 600 nm with near-unity luminescence efficiency. Photophysical characterization and theoretical calculation confirm efficient luminescence can be assigned to the synergistic effect of intermolecular energy transfer from triplet excitons of CDs to singlets of subluminophores and the intense restraint in nonradiative decay losses of singlet/triplet-state excitons via rationally space-confined rigidification and amination modification. By utilizing precursor engineering, yellow and near-infrared afterglow centered at 575 and 680 nm with luminescence efficiencies of 94.4% and 45.9% has been obtained. Lastly, these highly emissive powders enable superior performance in lighting and information security.