<p>Polymeric melon, a heptazine-based carbon nitride, has attracted increasing attention as a sustainable metal-free semiconductor for electronic, optoelectronic, and energy storage applications. Yet, its fundamental optical and electronic characteristics remain debated, particularly regarding the intrinsic nature of photon absorption and the energetic positions of trap states. Here, a unified analytical framework combining Tauc analysis, Jacobian-transformed photoluminescence spectroscopy, and first-principles calculations is employed to clarify the transition mechanism and trap-state energetics in melon nanoparticles. The results reveal that photon absorption in melon arises from both an indirect and direct electronic transition depending on the selection of precursor monomers, and that shallow trap states, located near the conduction band, play a dominant role in carrier recombination dynamics. These findings reconcile longstanding inconsistencies in reported bandgaps and provide a reliable basis for interpreting optical excitation and charge-transport behavior. This integrated approach advances fundamental understanding of charge-carrier dynamics in polymeric melon and provides a broadly applicable strategy for evaluating optoelectronic processes in polymer semiconductors and related nanomaterials.</p>