TECHNOLOGY FOCUS - IMAGING AND COMMUNICATION - Preferred Device: When the sulfur-organic compound is mercaptoacetic acid, then the preselected orientation (preferably at least 80% of (A)) is parallel to the surface. When the sulfur-organic compound is 2-mercaptoethanol, then the preselected orientation (preferably at least 70% of (A)) is perpendicular to the surface in the up position.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Substrate: The substrate is a metal, metal-coated substrate, silicon, metal silicide or tin oxide (preferably a gold-coated substrate). SPECIFIC COMPOUNDS - Mercaptoacetic acid, 2-mercaptoethanol and 2-dimethylaminoethanethiol are specifically claimed as the sulfur-organic compounds.    EXAMPLE - A molecular self-assembly was used both to anchor two dimensional arrays of photosystem I (PSI) reaction centers, to an electrode (an Au(111)) substrate, and to obtain a controllable orientation. Thylakoid membranes were isolated from spinach leaves as given in Methods Enzymology, S.G. Reeves and D.O. Hall, 69,85 (1980). PSI reaction centers together with their antenna complexes containing about 40 chlorophylls per photoactive P700 (PSI-40) were isolated from the thylakoid membrane. PSI was eluted in a buffer solution (0.2M phosphate, pH 7 containing Triton X-100 (detergent) (0.05%). P700 concentration was determined using the chemically induced absorbance changes at 697 nm and a differential extinction coefficient of 64 M-1 cm-1. Chlorophyll content was determined in 90% acetone extract. The Au(111) electrode was epitaxially grown by evaporation of 120 nm of gold onto freshly cleaved mica heated to 300 - 400degreesC in high vacuum. The gold substrate was immersed in a 10 mM solution of mercaptoacetic acid for 30 seconds to form a negative surface. The substrate was rinsed with nanopure distilled water and dried. Then the substrate was incubated in the PSI solution for 12 hours. The same cleaning and drying processes was applied after the sample had been taken out of the PSI solution. For comparison, a control samples were taken at each major step: (i) after gold evaporation; (ii) after surface modification and the cleaning/drying processes; and (iii) after incubation in a buffer solution without PSI. The control sample demonstrated that the measured phenomena were caused by the presence of oriented centers and were not artifacts of the experimental arrangement. The PSI % coverage on the self-assembled gold electrodes was calculated. These samples were incubated in the PSI solution for 12 hours. The experiment for PSI % coverage was repeated five times. It was found that 65+/-7% of the area was covered with PSI when electrode was treated with mercaptoacetic acid. This chemical treatment covered the gold surface with negatively charged end groups that attract and orient PSI. Then the PSI orientation for chemically treated gold electrode was found. The result indicated that when gold electrode was treated with mercaptoacetic acid, 83.1% of the PSI were anchored parallel to the surface, 9% were up and 7.9% were down.