New quinolinium semi-organic compounds of formula (C9H8N) 2+· SO42-, H2O (I)(bis- quinolinium sulphate monohydrate) and (C9H8N)+· NO3-(II)(quinolinium nitrate) have been synthesized and characterized by UV–Vis absorption spectroscopy, nonlinear optical (NLO) measurements and by single crystal X-ray diffraction. The third order nonlinear optical properties of (I) and (II) were investigated using two methods: the degenerate four wave ...
