N-Bridge Head Indolizin (Benzindolizin)-ium Iodide as Privileged Precursor in Heterocyclic Cyanine Dye Synthesis

3-Methyl-1-phenyl-pyrazolin-5-imin-4 (2)-indolizine (benzoindolizine)-zero-3 (4)-methine (27).3-methyl-1-phenyl-pyrazolin-5-imine-4 (2)-indolizine (benzo- indolizine)-B-substituted di-1- [2 (4)] methine cyanine dyes (28a-d).3-methyl-1-phenyl-pyrazolin-5-imine-4 (2)-indolizine (benzo indolizine)-? (?) disubstituted- bis-di- [2 (4)] methine cyanine dyes (30a-f) were synthesised based on 4-acetyl-1, 5-dimethyl-3-phenyl-3, 4-di [H] pyrazolo [4', 3':5, 6] pyrido [4, 3-b] indolizin-6-ium iodide& 4-Acetyl-1, 5-dimethyl-3-phenyl-3, 4-di [H] Pyrazolo [4', 3':5, 6] pyrido [4, 3-b] indolizin-6-ium-iodide (26a, b)& 1, 5-dimethyl-3-phenyl-3, 4-di [H] pyrazolo [4', 3':5, 6] pyrido [4, 3-b] indolizin-6-ium-iodide-4-?-substituted-?, ?-unsaturated carbonyl derivatives (29a-f). The new synthesized cyanine dyes were identified by elemental& spectral analyses. The UV-visible absorption spectra of some selected dyes were investigated in pure organic solvents and in aqueous universal buffer solutions.