For the aqueous THF solutions of TCNQ and melamine, the two peaks of DCTC -located at wavelengths of 282 and 485 nm are dominant, in addition to the strong UV absorption edge of melamine at 250 nm. Figures 3e shows the UV-Vis spectrum of a single crystal of doped melamine prepared with a mole percentage of TCNQ to melamine of 1.25 %. The absorption edges observed at wavelengths of 385 and 505 nm (indicated by the red vertical bars) can be attributed to TCNQ and DCTC -, respectively. In the crystal, both TCNQ and DCTC - seem to be present.