The cohomological rigidity problem for toric manifolds asks whether the integral
cohomology ring of a toric manifold determines the topological type of the manifold.
In this paper, we consider the problem with the class of one-twist Bott manifolds to
get an affirmative answer to the problem. We also generalize the result to
quasitoric manifolds. In doing so, we show that the twist number of a Bott
manifold is well-defined and is equal to the cohomological complexity of the
cohomology ring of the manifold. We also show that any cohomology Bott
manifold is homeomorphic to a Bott manifold. All these results are also
generalized to the case with Z(2)–coefficients, where Z(2) is the localized ring at
2.