Rietveld analysis and intermolecular energy minimization were used to refine the crystal structure parameters of one of the polymorphs of titanylphthalocyanine (TiOPc), which is a highly photosensitive pigment used in electrophotography. The most probable crystal structure is proposed to be a monoclinic unit cell, space group P21/c. The unit cell parameters are a=1.385 nm, b=1.392 nm, c=1.514 nm and β=120.22°. There are four molecules per unit cell.