In this study, we reported the design and the fabrication of Ag and TiO2 modified polycaprolactone (PCL) electrospun nanofiber (NF) mats. The as-prepared NF mats were fabricated by one-step electrospinning and it was exploited for three different purposes (i) reusable SERS substrate for quantitative analysis to trace organic pollutants, (ii) photocatalyst for degradation of organic pollutants and (iii) antibacterial agent for killing of bacteria. Three different nanofiber mats, PCL, PCL-TiO2, PCL/TiO2-Ag NFs. were fabricated and further investigated. The morphologies and structures of the as-prepared nanofiber mats were carried out using X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX) and fourier transform infrared spectroscopy (FT-IR) techniques. PCL/TiO2-Ag NFs served as a highly effective SERS platform with a detection limit of 10 nM for the detection of methylene blue dye (MB). A remarkable feature of the presented platform is the ability to reuse the PCL/TiO2-Ag NFs for SERS analysis of MB; availing from its capability for self-cleaning under UV light. By employing PCL/TiO2-Ag NFs nanocatalyst, complete photocatalytic degradation of the probe analytes MB and ibuprofen (Ibu) under UV irradiation was accomplished not more than 180 min. Moreover, PCL/TiO2-Ag NF mats showed a highly promising bactericidal feature against gram-negative Escherichia coli and gram-positive Staphylococcus aureus bacteria, which immensely emerged due to the presence of Ag NPs. This new trending nanofiber is assumed to lead a bunch of changes in the field of photocatalytic, SERS and antibacterial studies.