Polystyrene and polyvinyl chloride thin films are explored as sample supports for extreme ultraviolet (XUV) spectroscopy of molecular transition metal complexes. Thin polymer films prepared by slip-coating are flat, smooth, and transmit much more XUV light than silicon nitride windows. Analytes can be directly cast onto the polymer surface, or codeposited within it. The M-edge x-ray absorption near-edge (XANES) spectra (40-90 eV) of eight archetypal transition metal complexes (M=Mn, Fe, Co, Ni) are presented to demonstrate the versatility of this method. The films are suitable for pump/probe transient absorption spectroscopy, as shown by the excited-state spectra of Fe(bpy)$_3^{2+}$ in two different polymer supports.