UV irradiation of chloromethyl styrene simultaneously crosslinks the polymer and generates aldehyde groups that can be employed for polymer surface functionalization through aldehyde-imine/hydrazone chemistry. Using this method, we successfully have functionalized nanoimprinted polymer patterns with dyes, nanoparticles, and enzymes. These surfaces were characterized by infrared (ATR-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), fluorescence microscopy, and enzymatic activity assays.