Alloxanthin, which has two triple bonds within its backbone, was studied by steady-state and femtosecond transient absorption spectroscopies. Alloxanthin demonstrates an S-2 energy comparable to its non-triple bond homolog, zeaxanthin, while the S-1 lifetime of 19 ps is markedly longer than that of zeaxanthin (9 ps). Along with corroborating quantum chemistry calculations, the results show that the long-lived S1 state of alloxanthin, which typically corresponds to the dynamic of a shorter carotenoid backbone, implies the triple bond isolates the conjugation of the backbone, increasing the S-1 state energy and diminishing the S-1-S-2 energy gap. (C) 2016 Elsevier B.V. All rights reserved.