In recent years, triangulenium dyes, the class of highly stabilized triarylmethyl carbocation compounds, has gained extensive popularity among researchers owing to their characteristic structural, physiochemical, and optical properties. The first derivative, trioxatriangulenium, initially reported by Martin et al., has since been further modified through the introduction of various functionalities to create derivatives with improved properties and cationic stability. Triangulenium dyes, with their long excited state fluorescence lifetimes (τ ≈ 20 ns), have found applications as efficient probes for fluorescence lifetime imaging (FLIM) and time-gated imaging. Furthermore, some reports describe their use as photo-induced electron transfer (PET) based sensors for pH and redox processes. Recently Bo et. al. also elaborated the PET mechanism for the development of triangulenium based quenchers with different structural designs and fluorescence lifetime based optical probe for water detection. While triangulenium dyes are still in their infancy as fluorescent probes for subcellular targeting and imaging, strategic chemical modifications can improve their potential for bio-imaging applications.