One goal of our research into the nanoengineering of molecular magnets is a detailed understanding of the relationship between the structure and composition of a system and its magnetic properties. An important variable that we have not exploited thus far is the identity of the atom providing the exchange link between the strongly interacting elements in a structure such as the planes or chains. Here we propose measurements on a new series of coordination polymers based on square layers of spins whose interplane links are provided by metal atoms. The ability to change the identity of the linking metal atom allows us to measure the effectiveness of each as a mediator of exchange in this context. The new series forming the basis of this proposal has the formula CuMF6(pyz)2(H2O)x, where M is a metal ion. We will probe magnetic transitions and dynamics in this novel system.