I saw a question in the Zoho CRM forums that I thought I'd answer:
I created a custom field in the Lead form for Product and it is linked to our Product list in Zoho so when we click on the field to fill it in for a lead, it pulls up our Product list. However, once I click on one product, it automatically populates the field with that product without allowing me to select additional products. (Our leads and customers are often interested in multiple products.) Is there a way to keep the field linked to our Zoho Product list and make it multi-pick?My answer
I'd recommend using the Products related list for this purpose. Here's a screencast showing you how. You can report on which products are associated to which leads by choosing both modules when creating a report.