We present a comparative study of nonlinear optical materials for terahertz pulse generation by optical rectification and detection by electro-optic sampling, with the aim to find a material the is best suited for the use together with femtosecond lasers operating at a wavelength of 1.5 μm. Three crystals are identified that fulfill the condition that the optical group velocity matches the terahertz phase velocity: the organic salt DAST and the inorganic semiconductors GaAs and ZnTe, the latter showing velocity-matching with the second harmonic of 1.5 μm. A combined figure of merit for optical rectification and electro-optic sampling is derived. For the three materials under consideration, we find numerical values of 4300 (DAST):110 (GaAs):370 (ZnTe), in units of (pm/V)2. We also present experimental evidence that the performance of DAST is an order of magnitude better than those of the inorganic semiconductors, and we present spectroscopic data in the terahertz range of DSMOS, a chemical derivative of DAST that may in the future also be used for terahertz applications.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.