Professor Crossley is an internationally recognised authority in the fields of porphyrin chemistry and molecular engineering. He has made seminal contributions to the understanding of porphyrin structure and has devised methods for controlled introduction of substituents into the porphyrin nucleus. More recently he has used this knowledge to design and synthesise large molecular and suprarnolecular assemblies that exploit the redox and photochemical properties of the porphyrins with the aim of producing molecular devices - a process often referred to as 'molecular engineering'. He has recently been awarded the highest research award of the Royal Australian Chemical Institute for research in Organic Chemistry, viz the Birch Medal in recognition of this work.