Toward bioluminescence in the near-infrared region: Tuning the emission wavelength of firefly luciferin analogues by allyl substitution

•Allyl-substituted luciferin derivatives were designed and synthesized.•Bioluminescence properties of allyl luciferin derivatives were evaluated.•The allylation of luciferins induced bathochromic shift of their bioluminescence.•The longest near-infrared bioluminescence emission wavelength was achieved.