To understand the non-radiative processes present in Ds, MECP optimization between angle changed from 1.12 • at S 2 minima to 126.74 • at MECP. Analyzing the nature of orbitals involved in MECP, it is noticed that S 1 at MECP is no longer a pure π-π * state but with a mixing of n-π * character which is expected from the non-planarity introduced in the MECP.