Graphene is an attractive candidate for many optoelectronic applications because of its high carrier mobility. An essential process for many applications is the dissipation of the energy of photo-excited charge carriers in graphene. With ultrafast terahertz spectroscopy, an optical method for probing photoconductivities on ultrafast timescales, we quantify relaxation rates and pathways [1]. Carrier heating is also highly efficient when intrinsic carriers are accelerated by a strong electric field [2], which is detrimental to high-frequency electronics, but can be used to uniquely efficiently generate harmonics of terahertz radiation [3]. A drawback of graphene is the absence of a bandgap; we demonstrate a new two-dimensional metal organic framework, which is semiconducting and supports high charge mobility [4]. [1] A. Tomadin, et al., The ultrafast dynamics and conductivity of photoexcited graphene at different Fermi energies, Science Advances 2018, 4 (5), eaar5313 [2] Z. Mics, et al., Thermodynamic picture of ultrafast charge transport in graphene, Nature Comm. 2015, 6, 7655. [3] H.A. Hafez, et al., Extremely efficient terahertz high-harmonic generation in graphene by hot Dirac fermions, Nature 2018 DOI: 10.1038/s41586-018-0508-1 [4] R. Dong, et al., Band-like transport in a 2D Metal Organic Framework, Nature Materials 2018, in print