Increased use of ionic liquids and polymeric solvents may help curb the volume of emissions from processes involving volatile organic solvents. More importantly, however, is their potential as unusual reaction media that will facilitate unprecedented chemistry. By way of illustration, central to the use of ionic liquids as solvent systems for reactive molecules is an understanding of their decomposition pathways. Perhaps the most significant and detrimental side reaction of many ionic liquids is their reactivity with basic or electron rich species. In many cases, deprotonation reactions or decomposition of the ionic liquid through electrochemical processes results in unwanted side reactions. This talk will document several of the important reactions of common cations used in ionic liquids with electron rich species, and will show that these problems can, in some cases, be circumnavigated. We have prepared new solutions of phosphonium ionic liquids containing reactive species such as borane and Grignard reagents, and have studied their reactivity in some detail. For instance, Grignard reagents form persistent solutions in phosphonium ionic liquids, and in this highly polar media, they undergo facile electron transfer reactions. Reactivity studies will be reported, featuring detection of diamagnetic and radical intermediates, and structural studies will also illustrate the important inter-ion interactions involving complex anions. Some results on Grignard reagents in polymeric solvents will also be discussed.