  We propose a mechanism to drive singlet-triplet spin transitions
electrically, in a wide class of graphene nanostructures that present pairs of
in-gap zero modes, localized at opposite sublattices. Examples are rectangular
nanographenes with short zigzag edges, armchair ribbon heterojunctions with
topological in-gap states and graphene islands with sp$^3$ functionalization.
The interplay between the hybridization of zero modes and Coulomb repulsion
leads to symmetric exchange interaction that favors a singlet ground state.
Application of an off-plane electric field to the graphene nanostructure
generates an additional Rashba spin-orbit coupling, which results in
antisymmetric exchange interaction that mixes $S=0$ and $S=1$ manifolds. We
show that modulation in time of either the off-plane electric field or the
applied magnetic field permits to perform electrically driven spin resonance in
a system with very long spin relaxation times.
