\listfiles
\documentclass[b5paper]{jarticle}
\usepackage{pdfcolparallel}

\def\iroh{色は匂へど散りぬるを我が世誰ぞつねならむ
有為の奥山今日越えて浅き夢見じ酔ひもせず}
\def\Iroh{\iroh\iroh\iroh\iroh\iroh\par\iroh\iroh\iroh\iroh\iroh\par}

\begin{document}

\Iroh

\Iroh

\begin{Parallel}{0.47\textwidth}{0.47\textwidth}
\ParallelLText{%
\begin{itemize}
\item 1
\item
\item
\end{itemize}}

\ParallelRText{
\begin{itemize}
\item 2
\item
\item
\item
\item
\item
\item
\item
\item
\item
\item
\item
\item
\end{itemize}}
\ParallelPar
\end{Parallel}

\Iroh

\end{document}
