Novel pyrrole-thiazole hydrazinyl derivatives (4a-4j) were investigated using density functional theory (DFT) calculations to explore their electronic structure, chemical reactivity, and stability. Geometry optimization and quantum chemical calculations were performed at the B3LYP/6-311G(d,p) level of theory. Frontier molecular orbital analysis was carried out to evaluate the HOMO-LUMO energies, energy gap, ionization potential, electron affinity, electronegativity, chemical hardness, softness, and electrophilicity index of the synthesized compounds. Molecular electrostatic potential (MEP) mapping was employed to identify the electrophilic and nucleophilic reactive sites within the molecules. Natural bond orbital (NBO) analysis was performed to investigate intramolecular charge transfer interactions and stabilization energies, revealing significant donor-acceptor interactions within the molecular framework. In addition, nonlinear optical (NLO) properties, including dipole moment, polarizability, and first-order hyperpolarizability, were calculated to evaluate the compound's optical response. The obtained theoretical results provided valuable insights into the electronic properties, charge delocalization, and reactivity patterns of the synthesized derivatives, highlighting their potential significance in medicinal and material science applications