We analyze the behavior in several solvents of a perspective metal sensor, namely benzonitrile (DMABN-Crown5), a derivative of 4-(N,N-dimethylamino) benzonitrile (DMABN) that exhibits a dual fluorescence due to a twisted intra-molecular charge transfer process. To this end, we extend a stochastic modeling previously employed for DMABN, in which internal degrees of freedom are coupled with an effective solvent relaxation variable. Evaluation of potential energy surfaces using advanced QM approach and estimates of dissipative parameters based on hydrodynamic arguments are discussed. Emission fluorescence is calculated by solving a diffusion/sink/source equation for the stationary population of excited state, and compared to experimentally measured emission fluorescence of DMABN-Crown5. (C) 2008 Elsevier B.V. All rights reserved.