The in situ complex formation between two novel long-chain Schiff bases with Ag(I) ion at the air/water interface and their transferred Langmuir-Blodgett films were investigated. The long-chain Schiff bases containing heteroaromatic benzimidazole (BSC18) and benzthiazole (TSC18) rings form stable monolayers at the air/water interface. Addition of AgNO3 in the subphase caused the complex formation of the Schiff base with Ag(I). The Schiff base containing benzthiazole group formed a 1:1 complex with Ag(I). Regular layer structures are formed in the LB films of the Schiff base ligand and Ag(I) complex. The TSC18-Ag(I) complex showed orange color, which was specific only for the combination of TSC18 and Ag(I). X-ray photoelectron spectrum (XPS) of the transferred LB film revealed that a 1 (BSC18):2 (Ag(I)) complex was formed in the case of BSC18, which was explained by the coordination of Ag(I) ion with imine and OH and with benzimidazole. While the LB film of BSC18 showed a well-defined layer structure, that of the Ag(I) complex did not.