The effect of conjugation between 1,2,3-triazole ring system and azaindene scaffolds (either indolizine or imidazo[1,2-a]pyridine) on fluorescence has been examined. Three novel 1,2,3-triazole–indolizine hybrids have been prepared either through the Chichibabin indolizine formation or using 1,3-dipolar cycloaddition of activated alkynes to a pyridinium N-ylide, while a structurally related 1,2,3-triazole-substituted imidazo[1,2-a]pyridine was obtained via the Chichibabin reaction. The structures of two of the 1,2,3-triazole–indolizine hybrids have been established by single crystal X-ray diffraction. All novel compounds were investigated using UV–vis spectroscopy. Comparison between the fluorescence of 1,2,3-triazole–azaindenes and the fluorescence of analogous azaindenes that lack the 1,2,3-triazole moiety has shown a twofold amplification of fluorescence as a result of incorporation of the 1,2,3-triazole ring system in the structure of the novel hybrids. The 1,2,3-triazole-susbstituted imidazo[1,2-a]pyridine exhibited a stronger fluorescence emission than related 1,2,3-triazole–indolizine hybrids, therefore the former compound’s sensing ability against metal ions was evaluated. The 1,2,3-triazole-substituted imidazo[1,2-a]pyridine showed selective detection towards Hg2+ and UO22+ with similar detection limits of approximately 4.5 × 10−5 M.