The demand of new materials and processes for nanofiber fabrication to enhance the performance of air filters is steadily increasing. Typical approaches to obtain nanofibers are Based on top-down processes such, as melt blowing, centrifugal spinning, and electrospinning of polymer materials.:However, fabrication of polymer nanofibers is limited with respect to either A sufficiently high throughput or the smallest achievable fiber. diameter. This study reports comprehensively on la fast and simple bottom-up process to prepare supramolecular nanofibers in situ inside viscose/polyester microfiber nonwovens. Here, selected small molecules of the materials class :of 1 3,5-benzenetrisamides are employed. The microfiber-nanofiber composites exhibit a homogeneous nanofiber distribution and morphology throughout the entire nonwoven scaffold. Small changes in molecular structure and processing solvent have a strong influence on the final nanofiber diameter and diameter distribution,and, consequently, on the filtration performance. Choosing proper processing conditions; microfiber-nanofiber composites :with surprisingly high filtration efficiencies of particulate matter are obtained. In addition, the, microfiber-nanofiber composite integrity at elevated temperatures was determined and revealed :that the morphology of supramolecular nanofibers is,maintained compared to that of the utilized polymer nonwoven,.