High-pressure infrared absorption has been measured in the single crystals Of (TEDA)(2)TCNQ(3) at room temperature. An energy gap of a direct type with the size of approximately 0.23eV is observed at ambient pressure. In the molecular-vibration region, the absorption peaks caused by the C=C stretching are observed at 1518 and 1504 cm(-1), suggesting that the excess electrons are less localized in this substance as compared with other 2.3 TCNQ complexes. The behavior of these peaks suggests that a phase transition takes place at 1.0 GPa. In the high-pressure phase the excess electrons tend to be more localized instead of being delocalized, as indicated by the increasing of the energy spacing of those modes. The charge-transfer degrees of the TCNQ molecules are estimated to be 0.60 and 0.80 (low-pressure phase) and 0.56 and 0.88 (high-pressure phase).