AbstractLayered ternary typeâII Weyl semimetals demonstrate promising applications in highâperformance and broadband optoelectronics, therefore it is crucial to gain insights into their photocarriersâ dynamics. In this work, the probing polarization dependence of nonâequilibrium dynamics in NbIrTe4 is investigated by using transient reflectivity spectroscopy. Following photoexcitation at 3.18 eV, the dynamical response of 1.59 eV probe pulse exhibits a strong dependence on probe polarization. The relaxation comprises two components: a rapid recovery of â0.6 ps attributed to the electronâphonon scattering, and an anomalous slow recovery spanning hundreds of picoseconds attributed to the photoinduced quasiâparticle. The polarization dependence of rapid relaxation time Ï is indicative of the inâplane anisotropy of electronâphonon coupling in NbIrTe4. The slow relaxation modulated by a latest reported 16 cmâ1 coherent phonon also shows strong probing polarization dependence, further revealing the anisotropic nature of electronâphonon coupling and the possibility of anisotropic lattice distortion, as well as photoinduced polaron, under ultrafast photoexcitation in NbIrTe4. The dynamical anisotropy in NbIrTe4 has provided valuable guidance for the application of NbIrTe4 in polarizationâsensitive nonlinear optics or optoelectronic devices and offers insights into the unique carrier transport as well as phonon transport properties of this newly established topological material.