A bis(diaryldiazomethane) substituted with amino groups was synthesized and used for the surface modification of diverse materials, such as polystyrene, polyethylene, titanium dioxide, and aluminum plate, giving amino-functionalized materials. These were subsequently reacted with phenyl isocyanate to give urea-functionalized materials, so that hydrogen peroxide could be reversibly bound, giving in turn antibacterial materials with high activity. These functionalized materials were characterized using a combination of XPS, IR, and NMR spectroscopy, and clear evidence for the crosslinking on the surface of materials was achieved. The crosslinking reaction in the deposited layer contributed to higher loadings of hydrogen peroxide, and hence the antibacterial activity of urea-functionalized materials significantly increased. This approach gives a new protocol to prepare high loading antiseptic/antibacterial materials and surfaces.