Photosynthetic reaction center (RC) is one of the most important proteins, because it is Nature's solar battery converting light energy into chemical potential in the photosynthetic membrane assuring conditions for carbon reduction in cells. Although it is developed in nanometer scale, and is working in nanoscopic power, this is the protein that assures the energy input practically for the whole biosphere on Earth. The extremely large quantum yield of the primary charge separation (close to 100%) in the RC offers a big challenge to use it in nanodevices. Results of structural (AFM, EM), optical, and electro chemical investigations on RC bio-nanocomposite materials based on different carrier matrices (e.g., CNTs, ITO) will be presented. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim