Ultrathin films of F‐bridged Al‐phthalocyanine polymer, (AlPcF)n, grown by the molecular‐beam epitaxy technique show unusual spectroscopic properties which can be described by the possibility of pseudomorphic layer formation at the thin‐film/substrate interface. A change in the electronic structure of the molecules of this layer is presumed to occur. The existence of the layer is directly related to the degree of epitaxy.