Thin films of protonated meso-tetraphenylporphine were studied by IR spectroscopy and contact atomic force microscopy. Thin films of protonated porphine were shown to contain large amount of bound water, the most of which, however, can be removed by hygroscopic CsI. All water bands of the IR spectrum of a thin film are similar to those of liquid water including the broad band at 2000–2400 cm1. The changes in the doublet at 1440 and 1473 cm–1 characteristic of the IR spectrum of tetraphenylporphine pressed with KBr tablet indicate the donor–acceptor interaction between its molecules in thin films. Spherical nanoparticles with a diameter of 30–80 nm, as well as larger nanoparticles with different plasticity of water–porphine core, were detected using atomic force microscope. These particles are formed in a solution and shape a peculiar relief of thin films upon their sticking and sedimentation; this relief is represented by the isolated nanoparticles, submicroscopic grains, and microscopic domains.