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Steady-state fluorescence measurements were used to examine the fluorescence quenching of 1, 4-bis [-(2-benzothiazolyl) vinyl benzene (BVB) by sodium salt of meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS) in the presence and absence of silver nanoparticles (Ag NPs). The energy transfer (ET) process’s emission intensities and Stern–Volmer constants (KSV) showed that Ag NP’s presence increased ET’s efficiency. The molecular structures of TPPS, TPPS, and BVB/TPPS were optimized using the DFT/B3LYP/6-311G (d) technique to elucidate the mechanism. The discovered optimized molecular structure proved that whereas TPPS and BVB/TPPS MSs are not planar because the porphyrin group in TPPS is rotated out by phenyl sodium sulphate, the BVB MS is planer. All of the theoretical BVB results and the acquired experimental optical results were very similar.

The Super-efficient fluorescence quenching of the dye, 1-(E)-styryl-2-(4-(2-(E)-styrylphenoxy) butoxy) benzene (alkoxy bridged styryl benzene) (PPPBB), by silver and gold nanoparticles (Ag NPs and Au NPs) are explored by the steady-state fluorescence measurements in methanol and ethylene glycol (MeOH and EG). The data showed that both radiative and non-radiative energy-transfer perform a key role in the fluorescence super-quenching mechanism. The Stern–Volmer quenching constants (Ksv) were calculated as 1.4 \(\times\) 1010, 1.2 \(\times\) 1010 M− 1 in MeOH and EG for Ag NPs, and 2.69 \(\times\) 108, 6.18 \(\times\) 109 M− 1 in MeOH and EG for Au NPs, respectively. Besides, the quenching sphere radius (r) values were calculated, via Perrin model of quenching, as 160,161 nm in MeOH and EG for Ag NPs, and 45, 85 nm in MeOH and EG for Au NPs, respectively. From active sphere radius results, one can conclude that the fluorescence resonance energy-transfer is responsible for super-quenching of PPPBB. Moreover, the fluorescence energy-transfer had an observable effect on the fluorescence super-quenching of PPPBB by AgNPs and AuNPs in EG more than in MeOH. These Super-quenching processes can pave the way for the usage of (PPPBB/ NPs) quenching systems in the energy transfer-based biosensors and essays with high degree of sensitivity.