We will focus on the existence of nontrivial solutions to the following Hamiltonian elliptic system {-Δu + V (x)u = g(v), x ∈ R2, - Δv + V (x)v = f(u), x ∈ R2, where V is a positive function which can vanish at infinity and be unbounded from above and f and g have exponential growth range. The proof involves a truncation argument combined with the linking theorem and a finite-dimensional approximation.