This plugin allows users to register contacts and companies within JIRA and pick them up in JIRA issues. It also allows to manage list of products, services and money. This plugin is commercial, it is supported and has huge plans for development.
Where can you use CRM for JIRA?
If you use JIRA for ServiceDesk you can use this plugin to get issue statistics in the context of customer's companies and to manage list of used equipment and software.
If you Use JIRA for project or sale management you can immediately get information on current or past sales and projects with specific customer. You can also use it to keep information about sold services and products.