The relaxation kinetics of the diffusion influenced reversible one step reaction A + A double left arrow(k-1)(k1) double right arrow A(2) consecutive two step reaction A + A double left arrow(k-1)(k1) double right arrow A(2) double left arrow(k-2)(k2) double right arrow C and two step parallel reaction A +A double left arrow(k-1)(k1) A(2), A double left arrow(k-2)(k2) double right arrow C in one dimension have been studied. All these two step reactions show a power law (t(-1/2)) asymptotics as in the one step case although one of the rate equation is linear. In both the two step cases, such power law kinetics can be observed if all the steps of a reaction are reversible. (C) 2003 Elsevier Science B.V. All rights reserved.