\documentclass[a4paper,12pt]{article}
\usepackage{amsmath}
\begin{document}
\begin{align}
A = \max\left{B \\
& C \right}.
\end{align}
\end{document}
My expressions B and C are so long that they need to be on different lines. But then TeX doesn't accept left and right braces being on different lines. What can I do?

\documentclass{...}and ending with\end{document}.In case the OP posted some code that isn't an MWE:
– May 16 '14 at 03:43\left(&\right)aroundamsmath'saligndelimiter (“&”). – Werner May 16 '14 at 03:46\bigldoes not work with braces. – boaten May 16 '14 at 03:57\bigl. – boaten May 16 '14 at 04:00