We describe herein the concept, principle, and experimental findings of the molecular tips for chemically selective STM. It has been shown that molecular tips allow chemically selective imaging based upon the hydrogen bond, metal coordination, and charge-transfer interactions between sample and tip molecules. The chemical interactions result in facilitated electron tunneling through overlapped wave functions between the sample and tip molecules. The molecular tips were successfully applied to differentiate nucleobases, metal ions, or frontier orbitals of porphyrins. The selectivity can be tailored upon designing functional groups of the tip molecules. In addition, the molecular tips enabled the conformational analysis and detection of intermolecular electron transmission from a single molecule to another adjacent single molecule.