It is proposed that chemical properties provide a valuable bridge for analyzing the relationships between chemical structure and biological activity. Whilst at SmithKline & French Laboratories (SK&F), the realization that many organic compounds participate in conformational and prototropic equilibria led to formulation of the concept of dynamic structure–activity analysis (DSAA). This latter concept was fruitfully applied to the design of the first H2 receptor histamine antagonist drugs, burimamide, metiamide, and cimetidine. The value of collaboration between industrial and university scientists to conserve industrial resources whilst stimulating chemical understanding is expounded. Further studies of chemical properties of H2 receptor antagonists led to the identification of diamino-nitroethene as a biostere for cyanoguanidine and to a correlation of activity with hydrophobicity and dipole orientation. The exploration of potential therapeutic applications for histamine H2 receptor ligands (other than in gastric acid secretion) is discussed for use in inflammation, or in the central nervous system, or in immunology. The background is described for the initiation of the 1-week medicinal chemistry summer schools.