A chemosensor, 2,2'-(1,4-phenylenedivinylene)bis-8-acetoxyquinoline (1), its fluorescent sensing behavior toward representative alkali ions (Na(+), K(+)), alkaline earth ions (Mg(2+), Ca(2+)), and transition-metal ions (Ni(2+), Cu(2+), Zn(2+), Hg(2+), Pb(2+), Cd(2+)) was intensively investigated. The compound (1) exhibited pronounced Hg(2+) selective on-off-type fluoroionophoric properties among the representative ions in DMF/ethanol (1:9, v/v) solution. Moreover, the highly Hg(2+)-selective fluorescence quenching property in conjunction with a visible colorimetric change from colorless to light yellow can be observed, leading to potential fabrication of both "naked-eye" and fluorescent detection of Hg(2+).