Drago's research covered both the theoretical and practical side of acid-base chemistry. He developed the E and C equation as a quantitative model for acid-base reactions. His group used a variety of physical methods to probe intermolecular interactions and helped pioneer NMR studies of paramagnetic systems. He contributed to the area of catalysis focusing primarily on chemical processes relevant to industrial applications.  Work in this field contributed significantly to the understanding of ligand – metal and metal – metal interactions and their influence on the mechanisms, activity, and selectivity of numerous transition metals catalyzed systems.
A video interview with Drago is available.