We are in the middle of a construction and the building being built will be divided in half. One side of the building will be a for-profit business specializing in snacks, smoothies, juices, etc. and the back part will be the offices and the classrooms for an education non-profit. No revenue has been generated for either. For tax purposes, do we assign the construction costs to the business or the non-profit? Or to both? Thank you so much for your help!

BOTH, on a 50-50 split.

Please clarify: who is "we" in this question - are you the construction company, or the owner of one or the other of these businesses, or the building owner? If you're the building owner and are looking to allocate costs between tenants, I would think you would do it by square footage with perhaps some adjustments for any special construction that either of them may require for the operations - such as extra plumbing or electrical if needed. I don't see how the nature of the tenant being non-profit or for-profit matters in this.