The main purpose of this study is to develop a sensitive and portable fluorescent sensor system with a fast response time to be used to detect a target analyte. An azo-dye (Basic Red 9) was selected as a model target molecule. The luminescence section of the fluorescent sensor system is composed of UpConverting NanoParticles (UCNP). These luminescent particles were covered by a “recognition element" which is a molecularly imprinted polymer (MIP) shell. MIP shell was synthesized by applying a controlled polymerization technique, namely RAFT polymerization. The MIP covered UCNP core-shell particles (MIP@UCNP) were then covalently attached on the surface of non-woven polyethylene/polypropylene (PE/PP) fabrics via azide-alkyne click coupling reaction. Reusable target molecule-recognizing fluorescent fabrics were therefore prepared. The materials attained in each synthesis step were characterized by TEM, SEM, SEM-EDX, XPS, FTIR and XRD methods. The binding performances were investigated by fluorescence spectroscopy, which yielded a LoD at a few-ppb level. The sensor system developed is (1) more sensitive than similar ones thanks to the well-defined attitude of the MIP shell, (2) user-friendly, portable, practical and low-cost owing to the covalent attachment of nanoparticles on the surface of fabrics.