Mesoporous films based on crystalline TiO₂ nanoparticles functionalized with a ruthenium dye are used as efficient mercury [Hg(II)] scavengers. Mercury scavenging from aqueous solutions at room temperature was monitored both optically and by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). In both cases, the scavenging was observed to be selective and efficient.