A range of Mn(III) π-allyl cations of the form (η5-cyclopentadienyl)manganese dicarbonyl-η3-allyl+PF6- has been prepared and characterized by IR and1H NMR. These compounds are available through two convenient synthetic avenues involving coordination and subsequent dehydration of allylic alcohols or protonation of 1,3-dienes. © 1990, American Chemical Society. All rights reserved.