Abstract—3-Phenyl-8-triphenylphosphoimino-and 2-triphenylphosphoimino-1-azaazulenes were prepared by the reaction of the corresponding 8-and 2-amino-1-azaazulenes with triphenylphosphine dibromide. The structure of 3-phenyl-8-triphenylphosphoimino-l- azaazulene was investigated by X-Ray crystallographic analysis and molecular orbital calculation. The P-atom has trigonal bipiramidal coordination and the intramolecular ...