On/off luminescence vapochromic selective sensing of benzene and its methylated derivatives by a trinuclear silver(I) pyrazolate sensor.

{[3,5-(CF3)2Pz]Ag}3 (1) films exhibit selective/reversible sensing of small-organic-molecule (SAM) vapors, which readily switch-on bright-green (benzene or toluene) or bright-blue (mesitylene) luminescence that switches-off upon vapor removal. Vapors of electron-deficient SAMs or non-aromatic solvents did not attain luminescence switching and were not adsorbed.