Luminescent mononuclear bipyridine platinum(II) complexes bearing linear alkyl chains, [Pt(CN)(2)(dC(n)bpy)] (n = 9 and 11) have been prepared and characterized. These complexes are soluble in various organic solvents and exhibit remarkable solvent dependence and concentration dependence of the luminescence at room temperature. Such solvatochromic luminescence is attributed to the formation of the excimer of the platinum complexes.