Jeffrey Reimers is a theoretical chemist of very great ability and originality, whose work receives wide international recognition. It is almost unparalleled in breadth and depth of elucidations of electronic and vibrational structure of complex materials. It ranges from fundamental chemical interactions to mutagenesis effects in proteins, to understanding of single molecule devices, to in depth interpretation of photosynthesis and to organic solar cells. He is invariably in close contact with experiment; this has led (inter alia) to collaboration in molecular memory design funded by INTEL. His work is underpinned by an ability to devise computational methods of great power.