Three multiconfigurational methods to deal with multielectron dynamics and reaction/nuclear dynamics are reviewed, together with their applications to molecules in intense fields. The first one is the multiconfiguration time-dependent Hartree-Fock method for multielectron dynamics of atoms and molecules, where the many-electron wave function is expressed as a linear combination of Slater determinants for different electron configurations. The anisotropic near-infrared induced ionization of a CO molecule is analyzed in terms of the effective potentials for natural orbitals. The second one is the time-dependent adiabatic state approach where the eigenfunctions of the instantaneous electronic Hamiltonian including the dipole interaction with an electric filed are used as expansion bases for nuclear dynamics. The method is applied to reveal the dynamics of various molecules in intense fields such as bond selective dissociation of C2H5OH. The third one is an extended multiconfiguration theory for a whole system consisting of electrons and nuclei. This method can yield the electro-protonic wave function of a hydrogen-containing molecule, such as CH3OH, that satisfies particle statistics of indistinguishable protons.