Charge transfer in collisions between dipole-bound CH3CN- negative ions and the polar target CH3NO2, is examined using a Penning ion trap. A long-lived CH3NO- ion signal is observed. It is argued that this results from creation of dipole-bound CH3NO2- ions that rapidly evolve into longer-lived ions that have predominantly valence-bound character. The charge transfer cross section is sizable, similar to 1.4 x 10(-12) cm(2), but is consistent with a simplified near-resonant charge exchange model. (c) 2006 Elsevier B.V. All rights reserved.