This work aims to establish a study on ammonium cations based ILs combined with organic and inorganic anions. This book is the innovative documents of ammonium based ILs which provide the research area of physical properties, thermochemical properties, Synthetic studies, their uses in chemical industry, research laboratory in chemistry and material science and pharmaceutical industries. The biological evaluation and toxicological studies of ammonium based ILs were presented for the safe use in all area. The computational overview shows their theoretical studies.