Photocrystallography is an important technique in modern structural chemistry. The most recent and impressive developments of this technique in "small molecule" crystallography have been in the study of metastable state structures. In August 2010, we carried out the first photocrystallographic neutron diffraction "proof of concept" experiment on SXD in which nitro group in [Ni(dppe)(n1-NO2)Cl] reversibly converts to the nitrito isomer [Ni(dppe)(n1-ONO)Cl] upon irradiation with 400 nm light at temperature between 100 ¿ 160 K. We have developed a new centre stick with LEDs mounted on it to facilitate the irradiation of the crystal using the top loading CCR. In our preliminary experiment we did not have sufficient time to optimise the experimetal conditions fully and obtain 100% conversion to the nitrito isomer. We seek a further 7 days of time to complete this important study.