Surface potentials of heat-treated ultrathin polyimide (PI) Langmuir-Blodgett (LB) films and semiconducting phthalocyanine LB films deposited on Au, Cr and Al electrodes were measured by means of the Kelvin-probe method in a dark vacuum vessel at various temperatures as a function of the number of deposited layers. The spatial charge distribution in these LB films was determined on the order of nanometer scale from the relationship between the surface potential and the number of deposited layers. The distribution of the density of electronic surface, states in these LB films was also determined. It was shown that the charge exchange phenomena at the metal/film interface are explained with taking into account the presence of the interfacial states within the range of about 1 nm from the metal/film interface. Finally we discuss the molecular-rectifying property of junctions using organic LB films sandwiched between Al and Au electrodes.