Upon S 0 −S 1 excitation, the pyrazoline derivative molecule (Z)-2-(4-nitrophenyl)-3-(1-phenyl-4,5-dihydro-1H-pyrazol-3-yl)acrylonitrile, abbreviated as PY-oCNNO 2 , can be transformed from its ground state trans (E) form to bended cis (Z) form. Similar to the case of the well-known family of the photochromic azobenzenes, such a molecular property can be employed to fabrication of photochromic polymers by suitable doping of the chromophores into polymer matrix. In this work, we prepared poly(methyl methacrylate) thin films doped with PY-oCNNO 2 and measured the characteristic for optical switchers dynamic and static photoinduced birefringence (PIB) phenomenon. Possible conformational states of PY-oCNNO 2 , energy barriers, and associated dipole moments were calculated using TD-DFT quantum chemical methods. The presented experiments show that pyrazoline derivatives constitute a prospective group of materials with a great potential for photonic applications.