Carbon allotropes have been a rich area of study over the last century.[1] From the sp3 allotrope diamond to the surge of sp2 allotropes, fullerenes, carbon nanotubes, and graphene, the study of the structure and properties of carbon allotropes have been a pillar for advancements in both chemistry and physics. Despite these major advancements, studies involving the incorporation of sp carbon allotropes remain limited. The all sp carbon allotrope, carbyne, constitutes a pure, linear chain of carbon atoms which can be described by either a polyynic (alternating triple and single bonds) or cumulenic (all double bonds) structure. Given the promise of an idealised carbon wire, carbyne‑type compounds have been a fruitful area of study in molecular electronics, however, have been limited by the incorporation of terminal aryl moieties which ‘lock’ the internal carbon chain into either polyynic or cumulenic forms.[2,3] The investigation of directly bound (chemisorbed) sp carbon chains would therefore allow a more wholistic perspective of the conductance properties of carbyne. One such way to achieve direct chemisorbed sp carbon contacts involves transmetalation from (trimethylphosphite)gold(I) acetylide precursors,[4] providing precedence for the direct incorporation of sp carbon chains of atomically defined lengths into scanning tunneling microscope break junctions. Herein, this presentation will showcase the synthesis of α,ω‑bis[(trimethylphosphite)gold(I)] polyynes as precursors which have allowed for the unprecedented electrical and structural characterisation of linear atomic carbon chains within Au|Cn|Au (n = 4 – 16) molecular junctions.