Two-dimensionally cross-linked Langmuir-Blodgett (LB) films of maleic acid copolymers and poly(allylamine) were prepared by employing a double-chain amine (1) as the monolayer template which was subsequently removed by thermal imide formation followed by extraction. Maleic acid copolymers used were poly(maleic acid-co-methyl vinyl ether) (PMAMVE), poly(maleic acid-co-styrene) (PMAS), and poly(maleic acid-co-ethylene) (PMAE). The polyion-complexed monolayers of three components, i.e., template amine 1, a maleic acid copolymer, and poly(allylamine), were formed at the air-water interface. Their monolayer properties have been studied by the surface pressure-area isotherm and fluorescence microscopy. The monolayers could be transferred on solid substrates. The polyion-complexed LB films were characterized by FT-IR spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and ellipsometry. Two-dimensional cross-linking to form a polymer network was achieved by imide formation through heat treatment under vacuum. SEM observation of a film with PMAMVE on a porous fluorocarbon membrane filter (pore diameter 0.1 mum) showed covering of the pores by two layers in the polyion complex state. Six LB layers were, however, required in order for the film not to be destroyed during the heat treatment. Extraction by chloroform followed by immersion in aqueous NaCl produced pin-hole defects in the film.