Fig. 1. Two perpendicular perspective views ((a) side view and (b) top view) of the same fragment of the doubly interpenetrated frameworks 1M@pyr (M^II = Fe, Zn) showing the bpben pillars, coordination centres and pyrene units. The two crystallographically distinct frameworks are represented in blue (network 1) and beige (network 2) colours, while the different pyrene molecules are depicted in red (pyr1) and green (pyr2) colours. Au centres are yellow spheres.