  We present calculations of the complex-temperature zeros of the partition
functions for 2D Ising models on the square lattice with spin $s=1$, 3/2, and
2. These give insight into complex-temperature phase diagrams of these models
in the thermodynamic limit. Support is adduced for a conjecture that all
divergences of the magnetisation occur at endpoints of arcs of zeros protruding
into the FM phase. We conjecture that there are $4[s^2]-2$ such arcs for $s \ge
1$, where $[x]$ denotes the integral part of $x$.
