Solution-processable organic semiconductors have been regarded as one of the key materials for achieving printed electronics where several different properties such as high mobility and good environmental stabilities are required. Dinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (DNTT) is well known as a high mobility and stable p-type semiconducting material. However, its solubility in organic solvents is low. Even its derivatives with long alkyl groups (for example, C10-DNTT) is only slightly soluble in organic solvents at elevated temperature, and thus it is difficult to deposit its thin film by solution processes. Recently, we have found that introducing a branched alkyl groups to DNTT at the 2-position is effective to enhance the solubility with keeping the molecular orientation favorable for the carrier transport. Here, we demonstrate the synthesis and characterization of DNTT derivatives possessing a series of branched alkyl groups with the different branching positions, i.e., 2-ethylhexyl (EH), 3-ethylheptyl (EHep), and 4-ethyloctyl (EO). We also discuss the correlation between the branching positions and the bulk or thin film properties including OFET device characteristics. Electronic structures of the DNTT derivatives are basically the same for all the derivatives, independent of the branching positions in the alkyl groups. Thin films of the DNTT derivatives can be readily deposited on the Si/SiO2 substrates by vapor- or solution- processes. Their FET characteristics were only slightly different with almost the same mobility of 0.3 cm2/Vs by spin-coating method. On the other hand, by vapor-deposition method, all the derivatives showed mobilites higher than 1 cm2/Vs, indicating that the newly-developed DNTT derivatives have certain potential as high-performance solution-processable organic semiconductors. Their similar motilities can be explained by similar packing structures elucidated by the thin film XRD measurements; in the in-plane XRDs, all three derivatives show a similar XRD pattern with three peaks, which are typical for the herringbone packing observed for various DNTT derivatives.