Ionic liquids (ILs) are organic salts that melt below 100 degree celsius. Owing to their popularity in recent years as alternative solvents to volatile organic compounds (VOC's) ILs have been receiving increasing attention. The purpose of this research is to synthesize and study the toxic effects of the mono- and diammonium phosphate and bis(trifyl)imide ILs on zebra fish eggs. Halide salt precursors were prepared by reacting an amine with an alkylhalide bearing the desired substituent. Mono- and diammonium halide salts bearing ether, hydroxyl and alkyl substituents were prepared this way. The halide salts were converted to the desired IL by metathesis with a metal salt or protic acid of the desired anion. The ILs were purified using different techniques depending on the anion. The structures of the ILs were confirmed using 1H, 13C and 31P NMR. The toxicity of the ILs was tested by immersing freshly collected zebra fish eggs into aqueous solutions of ILs of varied concentrations. The development of the eggs was studied over a period of one week and was used to gauge the toxicity of the IL. Preliminary results indicate that ILs with longer alkyl chains tend to be more toxic than those with shorter chains. This project was supported by PSC-CUNY award # 69605-00 38.