On the basis of the highly reproducible scanning tunneling microscopy (STM) images, the anchoring structures of a homologous series of liquid crystals,n-alkylcyanobiphenyls (mCBs) are clearly divided into two categories; a single-row type and a double-row type. We have proposed that the single-row is the anchoring structure of a nematic phase, while the double-row is the one of a smectic phase. Furthermore, a new phase transition only available at the boundary has been confirmed for the first time in the binary mixtures. The correlation between those anchoring structures and the bulk phase diagrams is discussed from the viewpoint of anchoring phase formation at a molecular level.