Layered transition metal phosphorus chalcogenides (TMPCs) are van der Waals materials that couple spin, charge, and lattice degrees of freedom, enabling a range of nonlinear optical and magnetoelectric effects. Their lack of inversion symmetry and antiferromagnetic ordering make them promising candidates for second harmonic generation (SHG) studies. In this project, we mechanically exfoliated thin flakes of CuCrP₂S₆ (CCPS), CuVP₂S₆, AgVP₂S₆, and AgCrP₂S₆ down to ~5–10 layers, with potential monolayer CCPS flakes identified. Using a femtosecond laser setup, we measured SHG under varying polarization conditions to probe symmetry and magnetic responses. Polarization-resolved SHG from bulk and few-layer CCPS revealed two- and four-lobe patterns consistent with χ² tensor predictions, but additional lobes emerged below the Néel temperature. These features indicate the presence of magnetic-dipole contributions beyond electric-dipole processes, highlighting SHG as a sensitive probe of spin–lattice interactions. Looking ahead, we aim to extend measurements to ultrathin flakes, apply external magnetic fields to disentangle electric- and magnetic-dipole contributions, and integrate CCPS with ferroelectric AlScN in device structures to test magnetoelectric switching. Together, these studies advance TMPCs as model systems for symmetry-driven nonlinear optics and functional device applications.