Bio-based polyurethanes (PUHs) derived from castor oil (CO) have emerged as promising materials due to their mechanical resistance and chemical inactivity; they have found tremendous application growth. The physical and chemical properties of polyurethane (PUH1–3) made from castor oil polyol (COP) and various polyols, such as 1,4-phenylene bis (2,4-dihydroxy benzylidene) azine (PDaz) or polyol of (epoxy castor oil (ECO) with PDaz) (Eaz) with hexamethylene diisocyanate (HMDI), are investigated and compared for their light emission and corrosion inhibition of mild steel (MS). Thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) are used to assess the differences in characteristics of different PUH forms. As a result of incorporating fluorescent hard segment azine PDaz into the polymer with various preparation …