The non fluorescent meso diaminophenyl 1, 3, 5, 7-tetramethyl BODIPY dye has been investigated and employed for picric acid sensing in constructive way by regenerating its fluorescence through PET hindrance. Strong enhanced emission signal was obtained as consequence of electrostatic association between BODIPY probe and picric acid with specific recognition among other explosive nitro aromatics. The probe shows 1:1 binding stoichiometry with picric acid and detection limit up to 0.65ppb.

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A new acridine based photoinduced electron transfer based fluorescent chemosensor for the detection of nitroaromatic compounds is reported. The probe exhibited high selectivity and sensitivity for the detection of picric acid over trivial explosive in CH3OH.

Three novel iminocoumarin derivatives with high quantum yield are synthesized from 3-benzimidazole substituted coumarin and different aromatic aldehydes. The photophysical behavior of the synthesized compounds was studied using UV-visible and fluorescence spectroscopy in polar and non-polar solvents. The compounds show absorption maxima at around 450 nm and emission maxima at around 500 nm. The quantum yields of compounds in dichloromethane and chloroform are more than 0.90. The absorption, emission and quantum yield of compounds are dependent on the polarity of solvents. Along with an intense absorption, these compounds show shoulder absorption peak in the studied solvents. The solvent polarity plots revealed the charge transfer process in the synthesized molecules from donor to acceptor. Density Functional Theory and Time Dependent Density Functional Theory computations have been used to have more understanding of the structural, molecular, electronic and photophysical parameters of the dyes. The dyes were characterized by FT-IR, (1)H NMR, (13)C NMR and mass spectral analysis.

Donor-π- acceptor styryl chromophores based on indole core were synthesized by Knoevenagel condensation of N-ethyl indole-3-carbaldehyde and different active methylene compounds. The absorption and emission properties of these dyes in different solvents were studied. The dyes displayed a broad absorption maximum in the UV and visible region between 397 and 469 nm with FWHM, 50 to 75 nm. Due to the extended π - conjugated systems this styryl chromophores shows strong intramolecular charge transfer characteristics. The dyes showed solid state emission and emission in solid state was red shifted as compared to their emission in less polar solvents. Density Functional Theory [B3LYP/6-311 + G(d)] computations were used to correlate the structural, molecular, electronic and photo physical parameters of styryl dye with experimental study. Synthesized dyes were confirmed by using FT-IR, H NMR,C NMR and HRMS spectral analysis.