Using an ab initio theoretical spectroscopy approach, we have determined the structures and electronic properties of two molecular wires capped by photochromic dithienylethenes, that have recently been synthesized and characterized. The calculations have been performed with a range-separated hybrid functional (CAM-B3LYP) combined to an extended atomic basis set, and using a solvent model for all computational stages. Not only, we were able to reproduce the position of the measured absorption bands for any closed/open combination, but also to understand why the doubly-closed form is present in the experimental conditions. (C) 2010 Elsevier B.V. All rights reserved.