The electrical conductivity and the charge transport in monolayers of n-alkyl cyanobiphenyls (nCBs, n = 9, 10), disc-like pyridinium tethered with hexa-alkoxy triphenylene (PyTp) and polymer derived from 2, 6-dihydroxy-3, 7, 10, 11-tetraalkoxy-triphenylene (PHAT) systems have been studied. The measurements carried out using current sensing atomic force microscope were analyzed using Simmons approach. We find that 9CB and 10CB show a transition from direct tunneling to injection tunneling with barrier height of 0.71eV and 0.37eV respectively, the PyTp shows injection tunneling with a barrier height of 0.15eV and the PHAT shows direct tunneling with a barrier height of 1.22eV.