A novel mixed alkali hydro-isocyanurate, KLi(HC3N3O3)center dot 2H(2)O was first prepared in AOH-BOH-H3C3N3O3 (A/B = Li/Na/K/Rb/Cs) system via a solvent-drop grinding method. KLi(HC3N3O3)center dot 2H(2)O shows a large second harmonic generation response (5.3 X KH2PO4) with an ultraviolet cutoff edge of 237 nm. More importantly, the bulk single crystal can be readily grown through water solution technique. Characterization of these crystals indicates that KLi(HC3N3O3)center dot 2H(2)O has a high laser damage threshold (LDT) (4.76 GW/cm(2)) and exhibits a large birefringence (Delta n = 0.186@514 nm), which reduces Type I phase-matching to 246 nm.