Abstract Dimethyl 1, 3-dithiole-2-thione-4, 5-dicarboxylate (DDTD) was synthesized and characterized using NMR, Fourier transform (FT)-Raman, Fourier transform-infrared (FT-IR) and UV spectroscopies. Resonance Raman spectra (RRs) were obtained with 341.5, 354.7 and 368.9 nm excitation wavelengths and density functional calculations were carried out to elucidate the π (S [BOND] C [BOND] S)[RIGHTWARDS ARROW] π*(S [BOND] C [BOND] S ...