Abstract The genus Cicer L. consists of 43 species of annual and perennial herbs in the monogeneric tribe Cicereae (Leguminosae). The genus affords considerable interest because C.arietinum, the most well studied and most vulnerable species to disease and pests, is the chickpea, an important crop and food for resource-poor farmers, especially in Asia. More than 200 natural products have been identified from the genus. This chapter describes the chemistry of Cicer and the function of thosecompounds with known biological activities especially in the context of micro-organisms and insects that are natural pests and diseases of the cultivated crop. Some compounds occur constitutively in healthy chickpea plants that present inbuilt defence to infection by a range of pathogens and insects. For example, although the pterocarpans, maackiain and medicarpin occurconstitutively they also increase in concentration when the plantis attacked by a fungus, nematode or bacterium. These induced compounds (phytoalexins) are either biosynthesised de novo or as recent work suggests are accessible from glycosides stored in vacuoles. While these phytoalexins occur in all species of Cicer a few produce a wide array of isoflavonoids including recently discovered compounds from the rare isoflav-3-ene and arylbenzofuran classes all of which show varying degrees of biological activity against pathogens of chickpea and all are inducible. The chemical ecology of the plant especially with relevance to agricultural applications is discussed. We also describe their distinct occurrence among Cicer species and indicate how knowledge about their biosynthesis can inform the taxonomy of the genus. The recent synthesis of the arylbenzofuran cicerfuran from novel stilbenes precursors has been achieved alongwith several analogues. Their importance beyond the defensive value to the plant has become apparent through biological activity testing against different micro-organisms and showsthat these compounds may provide valuable novel activity against bacteria, fungi and protozoans. The chapter will also discuss some aspects of chemical synthesis of flavonoids of structural relevance to Cicer L.