Synthesis and characterization of novel squarylium dyes

Squarylium dyes based on 2,6-di-tert-butylpyrylium and 2,4-di-tert-butylpyrylium nuclei have been synthesized and characterized by elemental analysis, 1H NMR, IRand electronic impact mass spectroscopy. The dyes exhibit high melting points, good solubility in organic solvents and absorption maxima in the range of 711¯763 nm with high extinction coefficients.