Heptalene is a non-planar bicyclic 12 pi electron system. It has two dynamic processes, Double Bond Shift (DBS) and Double Ring Inversion (DRI), which lead to four interconnective isodynamic structures. The non-planarity of the two rings in heptalene is responsible for their inherent chirality and stimulates the experimental investigation of the question whether the heptalene backbone would be useful as a template for bidentate ligands for homogeneous transition-metal catalysis. In this book, we aimed first at synthesis of diphenylheptalene derivatives, taking the corresponding azulenes as their precursors, which could be available by introducing several substituents at the peri-positions of azulene. Later on, a number of diphenylheptalene derivatives were synthesized. This book may suit to the teachers and students in chemistry as well as the scientific researchers whose professions are related.