When  creating a contact when emailing a lead(near Send a Message), does not create the contact properly. The last name of the contact will be the email address. So you email a lead which prompts the user to create a contact for the lead first. When you create the contact and enter the lastname and first name the contact is created. But when you then check the contact, the fullname will be replaced by the email address and the last name is replaced with the email address.

see below code....In crm_lead.py

def message_get_suggested_recipients(self, cr, uid, ids, context=None):

recipients = super(crm_lead, self).message_get_suggested_recipients(cr, uid, ids, context=context)

try:

for lead in self.browse(cr, uid, ids, context=context):

if lead.partner_id:

self._message_add_suggested_recipient(cr, uid, recipients, lead, partner=lead.partner_id, reason=_('Customer'))

elif lead.email_from:

self._message_add_suggested_recipient(cr, uid, recipients, lead, email=lead.email_from, reason=_('Customer Email'))

except (osv.except_osv, orm.except_orm): # no read access rights -> just ignore suggested recipients because this imply modifying followers

pass

return recipients

Steps to go :

1. first go to leads  in crm module.
2. create a lead with subject, contact name(which includes first name, last name, title), and email. 
3. save the lead with out providing customer or partner_id.
4. go to send a message (in Open Chatter)

​ <div class="oe_chatter">
                    <field name="message_follower_ids" widget="mail_followers"/>
                    <field name="message_ids" widget="mail_thread"/>
                </div>

     5.  Here we can see the Contact Name or Email ("Name <email@address>")

 def _create_lead_partner(self, cr, uid, lead, context=None):
        partner_id = False
        if lead.partner_name and lead.contact_name:
            partner_id = self._lead_create_contact(cr, uid, lead, lead.partner_name, True, context=context)
            partner_id = self._lead_create_contact(cr, uid, lead, lead.contact_name, False, partner_id, context=context)
        elif lead.partner_name and not lead.contact_name:
            partner_id = self._lead_create_contact(cr, uid, lead, lead.partner_name, True, context=context)
        elif not lead.partner_name and lead.contact_name:
            partner_id = self._lead_create_contact(cr, uid, lead, lead.contact_name, False, context=context)
        elif lead.email_from and self.pool.get('res.partner')._parse_partner_name(lead.email_from, context=context)[0]:
            contact_name = self.pool.get('res.partner')._parse_partner_name(lead.email_from, context=context)[0]
            partner_id = self._lead_create_contact(cr, uid, lead, contact_name, False, context=context)
        else:
            raise osv.except_osv(
                _('Warning!'),
                _('No customer name defined. Please fill one of the following fields: Company Name, Contact Name or Email ("Name <email@address>")')
            )

 6.  But here name and email address are coming same, for  example rohit@gmail.com<rohit @gmail.com> but here we need to be rohit(rohit@gmail.com).

7.  see message_get_suggested_recipients code for it.