Organic solvent nanofiltration (OSN) is an energy-efficient membrane technology used in pharmaceutical applications for separation and purification. It offers advantages such as low energy consumption, low solid waste generation, and ease of scale-up. This review summarizes recent advancements in OSN, including its use in API concentration, catalyst recovery, solvent exchange, and peptide/oligonucleotide synthesis. OSN membranes are categorized into polymeric, inorganic, and mixed matrix types, each with distinct properties. The review discusses the fundamentals of OSN, including membrane processes, performance characterization, and separation mechanisms. It also highlights the challenges and future perspectives of OSN in pharmaceutical manufacturing. The review emphasizes the potential of OSN to improve sustainability and energy efficiency in pharmaceutical processes. The applications of OSN in API purification, including the removal of genotoxic impurities and oligomeric impurities, are detailed. Additionally, the review discusses the recovery and recycling of homogeneous catalysts using OSN, which offers advantages over traditional methods in terms of energy efficiency and environmental impact. The review concludes that OSN has significant potential to revolutionize pharmaceutical manufacturing by providing a sustainable and efficient separation and purification method.Organic solvent nanofiltration (OSN) is an energy-efficient membrane technology used in pharmaceutical applications for separation and purification. It offers advantages such as low energy consumption, low solid waste generation, and ease of scale-up. This review summarizes recent advancements in OSN, including its use in API concentration, catalyst recovery, solvent exchange, and peptide/oligonucleotide synthesis. OSN membranes are categorized into polymeric, inorganic, and mixed matrix types, each with distinct properties. The review discusses the fundamentals of OSN, including membrane processes, performance characterization, and separation mechanisms. It also highlights the challenges and future perspectives of OSN in pharmaceutical manufacturing. The review emphasizes the potential of OSN to improve sustainability and energy efficiency in pharmaceutical processes. The applications of OSN in API purification, including the removal of genotoxic impurities and oligomeric impurities, are detailed. Additionally, the review discusses the recovery and recycling of homogeneous catalysts using OSN, which offers advantages over traditional methods in terms of energy efficiency and environmental impact. The review concludes that OSN has significant potential to revolutionize pharmaceutical manufacturing by providing a sustainable and efficient separation and purification method.