In this paper we investigated the coherent electronic transport properties of molecular bridges where the tape-shaped oligoporphyrin molecular wires, called as the tape-porphyrins, are bridged between the two gold electrodes by thiolate (S-Au) bonds. In particular, we focused on effects of the chemical contact at molecule/electrode interfaces on the transmission spectra. Namely, we studied the dependence of the transmission spectra on the atomic sites where S-Au bonds are connected to the tape-porphyrin molecule, and their dependence on the additional spacing functional group between the tape-porphyrin molecular edge and the S-Au bonds. When the S-Au bonds are connected to the meso atomic sites of the tape-porphyrin molecule, several resonant peaks with large amplitudes are observed around the Fermi level, which indicates that the assumed molecular bridge is conducting even at lower bias voltages. As long as they are connected to the meso sites, the transmission peaks do not change their amplitudes significantly, even if the phenyl ring is inserted between the S-Au bond and the tape-porphyrin. However, if the bulky substituents are additionally introduced at the β atomic sites, the steric rotation of the phenyl ring is considered to dramatically suppress the transmission through the molecular bridge. [DOI: 10.1380/ejssnt.2003.45]