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Applications of organic semiconductors are extensive, including organic photovoltaics and organic field effect transistors. Controlling the organic semiconductors’ optical and electronic properties is critical for device performance. Here, select organic semiconductors were modified to develop new materials with enhanced properties.Fluorinated azadipyrromethene derivatives were synthesized and the electronic and optical properties of their respective zinc(II) and BF2+ chelates were studied. In two complexes, it was found that the addition of fluorine elements raised the oxidation and lowered the reduction potentials, while the addition of fluorine had little effect on the absorption spectra of solutions and films. Preliminary results in organic photovoltaics suggest that fluorine has a favorable impact in organic photovoltaics, but further research is required. Selective thionation of the distal carbonyls using a combination of core and imide substituents on naphthalene diimide (NDI) was demonstrated. Each addition of sulfur causes a 50 nm bathochromic shift of the visible absorption band and an anodic shift of the reduction potentials. Thionation of carbonyls offers a useful avenue for tuning NDI-based materials for opto-electronic applications. Initial synthetic work and characterization of a thionated NDI copolymer, P(ONDI-2S-T2) was performed. The initial results show that thionation of NDI copolymers potentially allows for greater light absorption in the visible region. Synthesis of functionalized poly(3-alkylthiophene) derivatives was performed to study the electrocoating of a semiconducting polymer. Thin films of functionalized P1 were successfully deposited over galvanized steel in a controlled fashion by a collaborator and the optical and dielectric properties of the P1 films were found to be similar to those of spin-coat poly(3-hexylthiophene). These results show that the process of electrocoating produced films as functional as those deposited by traditional techniques.