In the frame of this Program we developed: 1.New intercalation compounds with electrochromic properties; 2.Organic-inorganic hybrids appropriate for the synthesis of ionic conductors; 3.Materials with spectrally selective properties suitable for solar absorbers; 4.Thin layers with optical properties. Intercalation compounds and ionic conductors were used for the assembling of electrochromic, photoelectrochromic, photoelectrochemical and hybrid electrochromic cells. A profound knowledge about the intercalation properties of transition compounds is basic for the development of electrochromic systems. In these systems, the change in the oxidation state of the oxide under electrical pulse is accompanied by the intercalation of ions from the electrolyte (solid, semi-solid or liquid). This process lead to a modulation of optical properties of the oxide. Electrochromism is therefore characteristic for the system oxide-electrolyte. The charge, imparted to the oxide by the electrical pulse, is compensated by the ions from the electrolyte. The study of intercalation materials and electrolytes with ionic and redox conductivity is basic for the development of the electrochromic systems. Redox electrolytes were prepared on the basis of nanocomposite gels, from organic-inorganic composites. Functioning of photoelectrochromic and photoelectrochemical cells depend on metal oxide with large intrinsic area, on which a light-sensitive dye is chemically attached. Due to the absorption of solar radiation in dye, the dye passes electrons to the nanocrystalline oxide. The electrolyte contain I-/I3- redox pair that pass the electrons to the dye and connects the electrical circuit between working and counter electrode. Redox electrolytes, solid (hole transporting) or polymeric, are essential for the functioning of these cells and were developed in the frame of this Program on the basis of organic-inorganic composites. Redox electrolytes were used also for the preparation of hybrid electrochromic cells composed from active electrochromic layer (in this case WO3), redox electrolyte and counter electrode. The counter electrode is in usual battery-type electrochromic cells a thin layer with intercalation properties, but in a hybrid EC cell is counter electrode a Pt layer on SnO2:F substrate. This is one of the major advantages and simplified the cell preparation. Combination of TiO2 photoanode with ruthenium bipiridil dye and the layer of WO3 enabled the production of a photoelectrochemical cell, which can operate like Graetzel and electrochromic cell. The basic components of the fuel cells for low temperature use (up to 150 degrees C) are protonic conductive membranes. They represent the essential part of the fuel cells where electrochemical reactions take part leading to water as a reaction product (H2 cells) and electricity. Our first intent was to prepare a membrane with properties equivalent to Nafion, one of the most known and used membranes in the fuel cells of this type. The same organic-inorganic nanocomposites on the basis of silica (as for redox electrolytes) but adequately modified were used for the synthesis of membranes. For the preparation of ionooptical systems and protonic conductors for the fuel cells we used the sol-gel approach. This is the essential part of the Program: we were interested in mechanisms of the sol formation, changing of sols to gels and gels further to oxides. The sol-gel enabled also the preparation of thin layers with special optical properties, as - for example - optical filters for automotive bulbs; coatings for solar absorbers that selectively absorb solar radiation and have small emissivity of heat radiation; layers with electrocatalytic properties that can be used in fuel cells and electrocatalysis.