Ultrafast spectroscopic techniques have evolved significantly, becoming essential tools for characterizing materials across the visible, infrared, and terahertz spectral regimes. Among these methods, incoherent nonlinear techniques, notably transient absorption/reflection spectroscopy, are widely utilized. These approaches involve observing population dynamics triggered by optical excitation using femtosecond pulses, enabling real-time measurement of material responses via transient absorption or reflection. However, coherent techniques, entail measuring the nonlinear material spectral response with precisely controlled phase relationships among multiple femtosecond excitation pulses. In contrast to traditional spectroscopic methods, coherent spectroscopy offers a more intricate understanding of materials by employing multiple precisely timed light pulses. This facilitates the measurement of both time-resolved population and coherence responses, allowing for the examination of spectral correlations, enhanced resolution of optically dense spectra, and the differentiation of contributions to spectral linewidths from homogeneous and inhomogeneous sources. This symposium aims to showcase materials research leveraging multidimensional coherent spectroscopies across the visible, infrared, and terahertz ranges. This research encompasses diverse materials, from organic and hybrid semiconductors to quantum materials.

optical properties