Projects to use biotechnologically produced materials have involved a combination of advanced, at times visionary technological feats to be accomplished with rather mundane problems, such as the materials’ production by e.g. industrial microbiology, or fermentation. The planned use of rhodopsins, i.e. photosensitive proteins from microbes, for opto-electronic engineering, is a good example. In the 1980s, scientists started collaborating with Wacker Chemie, a German company that was among other things active in the silicon business, to pioneer such uses of rhodopsins. And whereas some seemed to think that such “molecular technology” might improve on then existing limitations of data storage or image processing, the first problems to be solved were production and purification of the substance on a relevant scale. The interest in rhodopsins should also be considered in light of biotechnological spirit of the time, as well as of political initiatives to foster the field in Germany after the development of recombinant DNA technologies in the US. Biotechnological production was considered an ecological alternative to the methods of the chemical industry, and uses of materials “designed by evolution” must have resonated well with the zeitgeist. Even if some of the schemes to employ rhodopsins seemed to have worked in principle, and various actors were involved, most projects were abandoned in the early 1990s and none is successfully commercialized to this day. Though this failure presumably resulted from different factors, it may allow to analyze specific problems inherent to production and uses of biological materials for “nanotechnological” purposes. Rhodopsins were considered both sensory receptors of organisms and a material substance targeted for technologies on a molecular level. With hindsight, this combination of biophysical and biochemical research with material engineering and information technologies seems to fit under the umbrella of “nano-bio-info-cogno convergence” (NBIC) that has recently been put forward. Thus, the rhodopsin case allows to contrast the at times abstract and normative debates on this prophesized merger of sciences and technologies with an historical example of an attempt to transform a biological substance into a material technology.