Solvatochromism, multiphoton fluorescence, and resonance energy transfer in a new octupolar dye-pair

► New octupolar dye DPATSP and its methyl derivative have been synthesized. ► Large change in the dipole moment (13D) is observed on excitation. ► High value of two-photon absorption cross section (600 GM) is observed for DPATSP. ► DPATSP with methyl derivative becomes a donor-acceptor pair for energy transfer.