Using the exponential decay of the conductance of a molecular wire with length and intramolecular quantum interference effects, a sample di-(9-amino, 10-hydro-anthracene)[a,c] naphtacene molecule OR logic gate is presented with no intramolecular rectifiers chemical group included. Embedded in a 3-electrode nano-junction, the molecule OR logic response is presented. The low bias voltage N-ESQC multi-electrode electronic transmission spectra are analysed based on this OR gate molecular orbitals structure. The logic '1' output running current reaches a large 100 nA intensity for a bias voltage of a few tenth of a volt. (C) 2009 Elsevier B. V. All rights reserved.