By using the time-resolved electric field induced optical second harmonic generation (TR-EFISHG) measurement system, we studied the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of metal-insulator-organic semiconductor diodes with a structure of indium tin oxide/Polyimide(PI)/6,13-Bis(triisopropylsilylethynyl)-pentacene(TIPS-pentacene)/Au. The TR-EFISHG directly probed the electric field across the TIPS-pentacene layer, and showed evidence of the charge accumulation at the TIPS-pentacene/PI interface region. Results of TR-EFISHG coupled with the I-V and C-V electrical measurements clearly demonstrated the rectifying properties and the threshold voltage shift of the diodes, before and after stress biasing. The results showed that the TR-EFISHG measurement coupled with the I-V and C-V measurements is a very useful way to analyze carrier behaviors and trapping charges of organic semiconductor diodes, even when the electrical property of the organic semiconductor layer is unknown. (C) 2016 Elsevier B.V. All rights reserved.