Fast pulse radiolysis transient absorption experiments were conducted on the ionic liquid methyltributylammonium bis(trifluoromethylsulfonyl)imide (R4NNTf2). The solvated electron was observed to have a very broad absorption band peaking around 1410 nm (epsilon = 2.2 x 10(4) L mol(-1) cm(-1)) and a radiolytic yield (G) of 0.7 x 10(-7) mol J(-1). Dry electron capture by aromatic solutes, such as benzophenone and pyrene, is very efficient in R4NNTf2. Reactions of the solvated electron with the same compounds are diffusion limited, with rate constants of only k approximate to (1-2) x 10(8) L mol(-1) s(-1) due to the high viscosity of the ionic liquid.