Owing to their humble chemical composition, carbon dots (CDs) can be readily synthesized from biomass, transforming waste into luminescent nanomaterials. In reforming biomass into CDs, the choice of solvent plays a critical role in bottom-up degradation, emulsion formation, surface structuring, and the physiochemical and optical properties of the CDs. However, there is a lack of understanding on the effect of solvents, particularly in the context of solvent-dispersed CDs that are of interest to optoelectronics applications. Here, a spatially confined carbonization of laminarin using oleylamine (OLA) as the solvent, exploiting ligand-carbon interactions, resulted in uniform (3.6 ± 1.5 nm) colloidal CDs exhibiting single crystallinity. Uniquely, the OLA-capped CDs show distinctive multiple emissions from blue to green and red simultaneously under UV excitation, demonstrating the intricate electron transfer and trapping from carbon core/functional groups to surface bound-ligand multiple emissions. The OLA-CDs can be stably dispersed in various solvents and facilely fabricated into thin-film devices. This work establishes the versatility and tunability of ligand-induced, spatially confined carbonization in forming colloidal CDs for optoelectronic devices from crude biomass.