Using a TD-PBEO/6-311++G(2d,2p) approach, we compute the absorption and fluorescence spectra of 1,8-naphthalimide in both gas-phase and ethanol. It turns out that the imide moiety only plays a marginal role in the emission spectra which is mainly related to a modification of the carbon-carbon pi bonding pattern. The computed fluorescence wavelength in ethanol (388 nm) is in very good agreement with the most recent measurement (384 nm). In addition, the adequacy of the CIS approach for computing the excited-state geometry is investigated together with the relevance of using smaller atomic basis sets. (c) 2007 Elsevier B.V. All rights reserved.