Optical and microstructural properties of electrodeposited molybdenum-copper (Mo-Cu) black coatings have been studied with reference to their selectivity in absorption of solar radiation. Such coatings were found to have a solar absorptance, alpha, about 0.87 and low thermal emittance, epsilon, such that the selectivity, alpha/epsilon, was 3.6. Electrodeposited molybdenum-black coatings generally have selectivity alpha/epsilon similar to 3. The oxidation state of molybdenum in (Mo-Cu) black coatings as determined by X-ray photoelectron spectroscopy is about +5 (which is fairly close to that of Mo4O11). Large numbers of irregular particles were found on the surface of molybdenum-copper black coatings. There is evidence that the particles contain copper oxide.