Polyaromatic quaternary ammonium salts (PQAS) are of significant interest due to their promising applications in biological and materials science. The incorporation of the heteroatom significantly modifies the electronic and chemical properties of the molecules, influencing their absorption and emission characteristics, as well as the HOMO-LUMO gap. Herein, we report the synthesis and photophysical investigation of [7]Helicene-backboned quaternary ammonium salts, which exhibit excellent stability, high fluorescence quantum yield, are redox-active, and have a structurally double helical axis. Single-crystal X-ray diffractometry has demonstrated the presence of a double helical structure within the crystal packing, which is characterized by the linkage of M-P and P-M heterodimers. For the investigation of energy relaxation and dynamics of the derivatives, we have measured the fluorescence lifetime, a key photophysical parameter that indicates their potential for detecting biological phenomena. Notably, these fluorophores turned out to be a potential biomarker, especially highly selective for lysosome imaging. To elucidate their electronic profiles, we employed time-dependent density functional theory (TD-DFT) calculations.