Near-field scanning optical lithography (NSOL) is a relatively new technique for patterning delicate organic thin films. Here, it has been used to fabricate a thin film optical phase grating in the semi-conducting polymer poly(p-phenylene vinylene). Recent advances in the development of the NSOL technique have been exploited to demonstrate its capability for producing photonic structures with nanoscale features despite the presence of a relatively large (200 nm diameter) NSOM tip. In particular, an intricate polymer photonic structure was designed (with fine scale features of the order of 250 nm) and then fabricated using the NSOL technique. The optical properties of the ideal phase grating were modelled and compared to the diffraction pattern produced by the fabricated structure. Comparison of the ideal and measured patterns showed the technique to be quite capable of consistently creating intricate polymer structures. The methodology employed represents a further step toward the construction of novel photonic devices.