Picosecond absorption spectroscopy is used to study the effect of solvent upon the dynamics of the contact ion pair formed upon bond heterolysis in diphenylmethyl chloride. The dynamics of the diphenylmethyl cation-chloride anion are probed in acetonitrile and propionitrile as a function of temperature. The Arrhenius parameters for the collapse of the contact ion pair to form the carbon-chlorine bond are A = 9.2 x 10(11) s(-1) and E(a) = 3.2 kcal/mol for acetonitrile and A = 5.1 x 10(11) s(-1) and E(a) = 2.8 kcal/mol for propionitrile. Deviations from equilibrium solvation transition state theory are found, and it is concluded that ion pair recombination occurs in the polarization caging regime.