0_8199             Long chain organic, organometallic and metal-containing polyynes are being constantly at the horizon of modern synthetic and materials chemistry. Such compounds are not only investigated as models for still elusive sp-carbon allotrope - carbyne, but have been proved to possess many unusual properties which extend from uncommon structural features to spectacular physicochemical behavior. In this regard, metal termini which are s-attached to the carbon chain play a crucial role in moderation of those properties. Especially interesting are red-ox active end-groups which use the unsaturated (CºC)_n bridge to communicate one with the other.             Numerous methods have been developed to synthesize polyynes and a plethora of such species was obtained and thoroughly characterized to date. We have lately focused our attention on 1-halopolyynes. This interesting group of rod-like compounds (1) possess an electrophilic terminal carbon atom which has an affinity to many nucleophiles and (2) undergoes oxidative addition to many metal complexes. Both these features have been used for a construction on new polyyne derivatives. One example would be iridium(III) or palladium(II) polyynes obtained via oxidative addition.             The others are selenium species formed via addition of in situ produced H₂Se to long chain aminopolyynes derived from 1-haloalkynes.             Since 1-halopolyynes are able to form strong halogen bonds we have been able to use this phenomena for a construction of planar architectures based on this non-bonding interaction.