Hi,
Essential Chart does not support customizing the Chart Title to have multiple lines or a subtitle directly. However, you can use any other control (like labels) to position them on the Chart to provide custom Titles and subtitles.
Please see the sample linked to below for an example:
http://www.syncfusion.com/support/user/uploads/F22402ChartMultilineTitle.zip
Thank you for your patience.
Regards,
Davis