  \noindent A paired coalition in a graph $G=(V,E)$ consists of two disjoint
sets of vertices $V_1$ and $V_2$, neither of which is a paired dominating set
but whose union $V_1 \cup V_2$ is a paired dominating set. A paired coalition
partition (abbreviated $pc$-partition) in a graph $G$ is a vertex partition
$\pi= \lbrace V_1,V_2,\dots ,V_k \rbrace$ such that each set $V_i$ of $\pi$ is
not a paired dominating set but forms a paired coalition with another set $V_j
\in \pi$. The paired coalition graph $PCG(G,\pi) $ of the graph $G$ and the
$pc$-partition $\pi$ of $G$, is the graph whose vertices correspond one-to-one
with the sets of $\pi$, and two vertices $V_i$ and $V_j$ are adjacent in
$PCG(G,\pi) $ if and only if their corresponding sets $V_i$ and $V_j$ form a
paired coalition in $G$. In this paper, we initiate the study of paired
coalition partitions and paired coalition graphs. In particular, we determine
the paired coalition number of paths and cycles, obtain some results on paired
coalition partitions in trees and characterize pair coalition graphs of paths,
cycles and trees. We also characterize triangle-free graphs $G$ with $PC(G)=n$
and unicyclic graphs $G$ with $PC(G)=n-2$.
