In this work, seven copolymers possessing thienothiophene and mesitylboron units were prepared. Incorporation of triphenylamine (TPA) and tetraphenylethene (TPE) into TT unit was probed to enhance their light-emitting efficiencies. Density functional theory investigations of the model compounds revealed the presence of an intramolecular charge transfer transition between the donor TT units and the boron acceptor atom. Among the seven TT-boron copolymers, four of them were used for the fabrication of polymer light emitting diodes 9PLEDs) and two of the devices exhibited pure white color according to the CIE. Although the efficiencies of the devices are low, as this study is the first example of thienothiophene inverted perpendicular inverted perpendicular-boron copolymers emitting white color, they are promising examples for future studies.