In this paper we report an in situ 2D visible-infrared sum frequency generation (VIS-IR SFG) study of the potentiostatic electrodeposition of gold from a solution containing [Au(CN)(2)](-) in 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl) amide ([BMP][TFSA]), a room-temperature ionic-liquid (RTIL). We followed the potential-dependent co-adsorption of BMP+ and CN-, released by reduction of the Au(I) complex, in the range -0.8 to 3.0 V vs. Au QRE. We found that the pyrrolidinium ring of BMP+ reorients as a function of potential value and interaction mode with coadsorbed CN-. The Stark tuning of CN- shows that this pseudohalide can be adsorbed in two different ways, that can be correlated with the presence of Au(I) reduction intermediates at the dynamic electrodeposition interface. (C) 2011 Elsevier B.V. All rights reserved.