Understanding the dynamics of electronically excited molecular states after optical excitation in organic semiconductors is necessary for improvement and optimization of potential molecule-based devices such as organic photovoltaic cells or organic light emitting diodes. Using femtosecond time-resolved spectroscopies, namely two-photon photoemission (2PPE) and second harmonic generation (SHG) we studied the exciton dynamics at interfaces with thiophene derivatives. For instance SHG, an interface-sensitive probe, is applied to investigate the photoinduced ultrafast charge transfer (CT) dynamics across the C60/P3HT interface. The de-excitation of hot singlet excitons in the conduction bands of the polymer into localized excitonic states is observed. In the presence of the electron acceptor, the ultrafast population of a CT state is identified as the dominating relaxation channel. Interestingly, the charge transfer yield correlates with the excitation wavelength and rises with increasing excess energy.