Among TTF derivatives, dithiophene-tetrathiafulvalene (DT-TTF) (Scheme 1) received considerable attention as an active material for organic field-effect transistors (OFETs) due to its high charge carrier mobility. In contrast to neutral TTF which exhibits a twisted boat-like conformation, the DT-TTF molecule is completely planar in the solid state, and its oxidation potential (E°1 ox = 0.78 V, E°2 ox = 0.96 V vs SCE) is higher than that of TTF leading to improved ambient stability. In order to optimise the OFET performance, one strategy consists of adjusting the electronic structure of the electroactive molecules to align their HOMO energy level with the work function of the electrode (e.g. 5.1 eV for gold). In this sense, the incorporation of electron-withdrawing or electron-donor groups is an efficient strategy to fine-tune the HOMO and LUMO energy levels. However, so far, no studies on the direct functionalization of DT-TTF building blocks allowing the modulation of its electronic structure have been reported. Scheme 1. Molecular structures of TTF and DT-TTF. Given the importance of TTF and DT-TTF based systems in organic electronics, the study of their organisation in thin films such as H-bond based self-assembled molecular networks (SAMNs) adsorbed on solid substrates is desired. The use of scanning tunnelling microscopy (STM) allows the direct visualisation of such SAMNs, enabling the study of their domain size, presence of defects as well as intermolecular bonding landscape. In particular, the self-assembly of TTF derivatives on conductive substrates such as highly oriented pyrolytic graphite (HOPG) has been studied previously. Herein we report the synthesis and characterisation of a family of arylated DT-TTF derivatives 2-5 (Scheme 2) obtained via palladium-catalysed direct C-H arylation. Monoarylation of DT-TTF introducing -NO 2 (2) or -NMe 2 (3) functional groups results in a decrease and increase of HOMO energy levels, respectively. Furthermore, the corresponding tetraarylated DT-TTFs bearing ester (4) or acid (5) groups have also been synthesised, both of them displaying a non-planar configuration as revealed by density functional theory (DFT) calculations. STM studies revealed that the DT-TTF-tetrabenzoic acid derivative 5 forms densely packed 2D self-assembled networks at the heptanoic-acid/graphite interface. Furthermore, molecular models based on experimentally measured unit cell parameters suggest that 5 lies flat on the graphite surface due to van der Waals interactions with the surface as well as H-bonding with neighbouring 5 building blocks.