Polyins, formerly known as polyactylenes, are relatively unstable organic compounds with several carbon-carbon triple bonds (analogous to polyenes with several C=C double bonds).
Prek. Well over 1000 naturally occurring polyins have been isolated. They occur in plants, fungi, bacteria, marine sponges and corals. In plants, polyins occur particularly in the families of Asteraceae(composites), Apiaceae (umbellifers), Hedera(ivy plants) and in Petroselinum crispum(parsley).
Biogenetically, poylins are formed by dehydration from oleic acid or other fatty acids. The simplest representative of polyins is diacetylene (butadiin).