We prove a weak form of the soliton resolution conjecture for — [Formula: see text] uniformly bounded in time — solutions of semilinear fourth-order Schrödinger equations, in dimensions [Formula: see text], and with a mass supercritical-energy subcritical power type nonlinearity, by using a strategy developed by T. Tao in 2007. More precisely, we prove that the solutions are decomposed into a sum of two terms: a free solution and a nonradiative term that approaches asymptotically an object that has similar properties to those of a finite sum of solitons. The asymptotic behavior of the nonradiative term is derived from its asymptotic frequency localization and its asymptotic spatial localization. There are two main differences between the present contribution and T. Tao’s earlier work. The first one appears when we prove the asymptotic frequency localization: we fill a gap of regularity by using the better dispersive properties of the high frequency pieces of the free solution. The second one appears when we prove the asymptotic spatial localization. A key estimate depends on the fundamental solution that does not have an explicit form. We overcome the difficulty by introducing a modified fundamental solution and exploiting the symmetries of the characters of the phases.