A perfume composition comprising an effective amount of at least one alkadienenitrile selected from 4,8-undecadienenitrile and isomers thereof, 4,9-dodecadienenitrile and isomers thereof, and 4,10-tridecadienenitrile and isomers thereof. The isomers of 4,8-undecadienenitrile comprise Z,Z-4,8-undecadienenitrile, E,E-4,8-undecadienenitrile, and mixed Z / E isomers of 4,8-undecadienenitrile; the isomers of 4,9-dodecadienenitrile comprise Z,Z-4,9-dodecadienenitrile, E,E-4,9-dodecadienenitrile, and mixed Z / E isomers of 4,9-dodecadienenitrile; and the isomers of 4,10-tridecadienenitrile comprise Z,Z-4,10-tridecadienenitrile, E,E-4,10-tridecadienenitrile, and mixed Z / E isomers of 4,10-tridecadienenitrile. A composition comprising an effective amount of at least one alkadienenitrile selected from 4,8-undecadienenitrile and isomers thereof, 4,9-dodecadienenitrile and isomers thereof, and 4,10-tridecadienenitrile and isomers thereof. Processes for the preparation of the isomeric alkadienenitriles are provided. The isomeric alkadienenitriles have a range of fresh, citric, ozonic and floral notes of exceptional strength.