Isoindigo (IID) and diketopyrrolopyrrole (DPP) are two of the most important acceptor units for constructing high mobility donor-acceptor (D-A) conjugated polymers. We have designed and synthesized IID- and DPP-based novel acceptor units such as isoindigo[7,6-g]isoindigo (DIID) as well as some polycyclic aromatics, e.g., dithienocarbazole (DTC) and dithienonaphthodithiophene (DTNDT), as donor units. Various D-A conjugated polymers have been synthesized for the fabrication of organic thin-film transistors (OTFTs) and polymer solar cells (PSCs). DTC and IID based polymers are promising donor materials for PSCs, which exhibited power conversion efficiency up to 8.2%. Compared to IID-based polymers which are unipolar materials, the polymers based on DIID displayed ambipolar transport properties as evaluated with OTFTs. We also developed a new thiophene derivative 1,2-bis(3,4-difluorothien-2-yl)ethane, which is highly reactive in direct arylation. High molecular weight DPP and IID-based conjugated polymers have been synthesized via direct arylation polycondensation with toluene as solvent. The resulting conjugated polymers were used to fabricate OTFTs which exhibited great ambipolar transport properties. Field-effect hole and electron mobilities of 3.40 and 5.86 cm2V-1s-1, respectively, have been demonstrated as measured in ambient conditions.