2[2‐(benzoxazonyl / quinoxalonyl) ‐ benzfurano (indolo)] ‐ quinolinium ‐1 ‐ ethiodide apocyanine dyes (Va‐f and VIa‐f) were prepared, via interaction of 2‐[2‐(benzoxazonyl‐/quinoxalonyl)‐1,2‐dibromoethenyl]‐quinolinium‐1‐ethiodide (IVa,b) with the appropriate phenols/and or arylamines. The new cyanines were identified by spectral determination. Bactericidal and fungicidal activity of selected cyanines (IIIa,b, Va, VIa, VIh, and VII) were tested against bacterial and fungal strains.

N‐Bridge Head Heterocyclic Precursors (2a‐f, 3, 6a‐f & 13) were used as main key intermediates in the synthesis of N‐bridge head heterocyclic mono‐2(4)‐or 3 [4(1)] methine (4a‐h, 5a‐c, & 7a‐h), cyclic mero‐6(4)‐linkage position (8) cyanine dyes and bis‐3,6‐mono[4(2)]methine linkage positions (10, 11 & 12) & tri‐3(4)‐methine cyanine dye (14).The spectral behaviour, solvatochromic & acid‐base properties of such dyes was discussed.

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Pyrano‐ and pyrylium mono‐8[4(1)] and/or 5(6)‐[2(4)]methine cyanine dyes (6a–k, 7a–f) were synthesized based on acyclic heterocyclic Schiff bases of pyrolo[3,2‐d]pyrazole[oxazole(imidazol‐6‐one)]‐1‐ium iodide salts, 5‐acetyl‐N‐aryl[pyrazolinyl(pyridinyl)]pyrolo‐[5,4‐d]pyrazolin‐iodide salts, and/or (anhydro bases) precursors (1a–i, 2a–I, 3a–i, 4a–i, and 5A,Ba–i). The structure of pyrylium‐9‐chloride and/or iodide and their pyrano(pyrylium)‐mono‐8[4(1)] and 5(6)[2(4)]methine cyanine dyes was identified by elemental and spectral data. The absorption spectra of some selected dyes were investigated in 95% EtOH, polar (nonpolar) organic solvents and in universal buffer solutions to investigate the optimal conditions for the application of such dyes as photosensitizers.

The benzoxazine or quinoxaline derivatives (V) are prepared as shown in the reaction scheme and coupled with (VI) to yield the benzofurano or indolo compounds (VII).