This work reports on the fabrication of organic thin-film transistors (OTFTs) with a solution-based 6,13-bis(triisopropylsilylethynyl)pentacene by a drop-casting method, and the determination of the electrical properties of OTFTs having different source/drain interdigitated-finger electrodes. The results show that the hysteresis in transfer characteristics of the OTFTs depends on the variation of contact fingers. These hystereses lead to changes in threshold voltage, which originates from charge trapping/detrapping at or near the organic semiconductor/dielectric interface. These related phenomena also influence the device parameters such as the field-effect mobility, the on/off current ratio, and the gate current.