to C8 (Table ) reveals that B3LYP values overestimate the conductance by upto 2 orders of magnitude, while CAM-B3LYP yields conductance within 1 order of magnitude of the experimental values. Nonetheless, B3LYP produces a negative β value of -0.136 which is in fair agreement with the experimental value of -0.120 from C4 to C8. The transmission characteristics for the lower members exhibiting CSS ground state (Figure ), indicates that the frontier transmission peaks approach towards Fermi energy with a decreasing energy gap in CSS state, while OSS converge to CSS with a slight variation for C12. For higher cumulenes in OSS ground state (Figure ), frontier resonance peaks in CSS state feature a contracting energy gap to 0.57 eV for C24, while transmission peaks in OSS state do evidence a gap saturation at ∼ 1.55 eV from C14 to C24 cumulenes. In addition to this, OSS state yields lower transmission peak heights than those of CSS state. This results in significantly decreased transmission near Fermi energy in OSS state as compared to CSS state. Notably, apart from the frontier transmission peaks residing near Fermi energy, all the transmission features away from the Fermi energy are nearly identical in CSS and OSS state, implying that spin symmetry breaking effects are negligible for those states.