Krebs' scientific achievements are centered in the fields of inorganic chemistry, bioinorganic chemistry, and structural chemistry. Starting with his thesis on trithiocarbonic acid and its chemistry, and supported by his profound experience gained during his postdoctoral work at Brookhaven National Laboratory, he was one of the pioneers of chemical crystallography in Germany in the sixties. In this context he was successful in his synthetic investigations on novel polynuclear metal-sulphur compounds, on chalcogen-halogen compounds and on transition metal oxo compounds which were supported by most innovative structural investigations with X-ray and neutron diffraction methods. In the field of physically relevant synthetic solid state chemistry he is internationally known for his pioneering development of boron-chalcogen chemistry. Besides novel binary and ternary boron-sulfur and boron-selenium compounds he developed new ionic conductors on the basis of lithium chalcogenoborates.
His work in bioinorganic chemistry is centered mainly on investigations of the synthesis, structure and function of model compounds for metalloenzymes such as the purple acid phosphatases (iron, zinc), glucose isomerase (cobalt, zinc) and copper type-3 enzymes (catechol oxidase, tyrosinase). These investigations have led to catalytically active models as thermally stable and selective analogues for metalloenzymes. One of the achievements is the establishment of  bio-analogous chemosensor systems for the analysis of catecholamines. Further investigations include a large number of mono- and polynuclear sulphur complexes of transition metals such as iron, nickel, cobalt, zinc or molybdenum.
They are significant contributions to the understanding of the function and structure of important metal-sulphur proteins such as ferredoxins, nitrogenases and metallothioneins. An important recent research project concerns the synthesis and practical development of novel platinum complexes as possible antitumor agents. Bernt Krebs was able to develop a number of highly interesting new compounds with promising properties, e.g., without nephrotoxic side effects.
His structural investigations are significant contributions to the understanding of the mechanisms of the interaction of platinum agents with DNA. The contributions of Bernt Krebs to the methods and applications of crystal structure analysis with X-ray and neutron diffraction and to X-ray absorption spectroscopy are outstanding. His pioneering crystal structures of purple acid phosphatase from kidney bean and of catechol oxidase from sweet potatoes have become classical results of metalloenzyme research papers.