Abstract
1-Methyl-4-(2-(4-(dimethylamino)phenyl)ethenyl)pyridinium iodide and its three analogues with ethyl-substituted cations were prepared. The solubility in organic solvents was confirmed to increase by ethyl substitution. Counter anion exchange afforded several SHG active crystals even in ethyl-substituted derivatives, and 1-ethyl-4-(2-(4-(dimethylamino)phenyl)ethenyl)pyridinium p-nitrobenzenesulfonate was estimated to have an off-diagonal d component twice as larger as that of 1-methyl-4-(2-(4-(dimethylamino)phenyl)ethenyl)pyridinium p-toluenesulfonate (DAST).