This review attempts to bridge the gap between primitive and modern LLPS systems, although the gap still remains large (Fig. ). For example, even though bottom-up approaches to study the formation of primitive coacervates exist, primitive phase separation has been rarely explored in the context of primitive disordered peptides, while coacervates formed using bottom-up approaches have hardly been compared with membraneless organelles in modern cells. Similarly, studies involving synthetic proteins mimicking modern IDPs that form in vitro coacervates are rarely correlated with disordered peptides that formed primitive LLPS systems on early Earth. Therefore, computational and experimental studies to explore these aspects along with other similarities/dissimilarities of primitive coacervates with modern membraneless organelles are necessary to connect primitive phase-separation with modern biology. In the context of OOL, ancestral reconstruction of ancient proteins is an emerging field that can help researchers understand primitive Earth conditions and the origin of the structure/function of modern proteins. Ancestral reconstruction of primitive LLPS-forming IDPs to produce prebiotic pre-LUCA disordered proteins that can phase separate is one approach that can be beneficial to explore this idea further. More closely comparing primitive and modern LLPS in such a systematic way may empower researchers to understand both these systems at greater depth, not only providing further answers on the mechanism both of life's origins and essential cellular processes, but also potentially facilitating an increase in the applicability of such systems in biotechnology, nanotechnology, and nanotherapeutics.