Gallium Nitride (GaN) substrates have recently been proposed as high performance substrates for surface enhanced Raman (SEAS) measurements. The GaN substrate acted as a template for nano-structuration of the surface, and a noble metal (e.g. silver or gold) supported the electrical fields and surface plasmon resonances deemed necessary for SEAS. However, we demonstrate here that charge transfer conditions can be approached with a selected molecule on pure GaN substrates, and that the surface plasmon resonances of the noble metals are not a prerequisite anymore to obtain SEAS conditions. We use a black dye (N719) adsorbed on GaN bundles of nano-wires for which the charge transfer resonances can contribute enhancement factors up to 10(4). The charge transfer (CT) transition from the GaN substrate valence band (-6.75 eV) to the molecular LUMO (-4.26 eV) is in resonance with the energy of the laser excitation at 488 nm (2.54 eV), and with the molecular resonance within the N719 molecule (omega(Mol) = 2.47 eV).