Is Landlord liable for tenants stolen property?

While My Commercial Landlord was painting and making repairs to the property that I had started moving out of, Several of my antiques were still in the back room of the property. My landlord, without notice or my permission, entered at will, as did workers, strangers and possible renters. The doors would be left open and the property (and my antiques) left unattended. There were several nice, big ticket items stolen. i.e. 2 huge Italian Tole floor lamps etc... Someone should have been noticed carrying these items out! We were moving a few items at a time and I have a witness to the fact that these items were there one day and not the next!

Is my landlord liable for these items? Should he pay me for them?

As long as you are still a paying tenant I would say yes. Even if you had given landlord permission I would argue he/she would still be liable if someone came in and stole things because door was left open for all to enter.

Had your lease term already expired then I would say no as the property is now back in the landlord's possession.