The response of ferromagnetic Ising polymer chain in dilute solution to external magnetic field is investigated using Monte Carlo technique. It is found that both magnetic and spatial conformational properties are dependent on the external field, chain length, and temperature. They behave differently at temperatures below and above the zero-field critical temperature 7, Simulation results indicate that the model chain is a possible candidate for recording material and molecular mechanism. (C) 2004 Elsevier Ltd. All rights reserved.