We study the dynamics of nonlinear oscillators indirectly coupled through a dynamical environment or a common medium. We observed that this form of indirect coupling leads to synchronization and phase-flip transition in periodic as well as chaotic regime of oscillators. The phase-flip transition from in-to anti-phase synchronization or vise-versa is analyzed in the parameter plane with examples of Landau-Stuart and Rossler oscillators. The dynamical transitions are characterized using various indices such as average phase difference, frequency, and Lyapunov exponents. Experimental evidence of the phase-flip transition is shown using an electronic version of the van der Pol oscillators. (C) 2012 American Institute of Physics. {[}http://dx.doi.org/10.1063/1.4729459]