Yes. If you have more than one email account with Zoho, even if the domains are different, you can now access both emails from the Zoho app for smartphone. eg) You own two companies, both with Zoho accounts: email@companyone.com and ...
Zoho provides multiple apps for mobile email access. The main Zoho Email app is available for Android or Apple OS. You can use it to access more than just your Zoho account as it offer POP3 and IMAP for external accounts like Gmail, Yahoo, Microsoft, ...