Observation of $\textit{ψ}$(3686) $\textit{→}$ + c.c.

Using a sample of (2$\textit{.}$712 ± 0$\textit{.}$014) × 10 $\textit{ψ}$(3686) events collected with the BESIII detector at the electron positron collider BEPCII, the decay $\textit{ψ}$(3686) → + $\textit{c.c.}$ is observed for the first time, which has a significance of 5.9 standard deviations. The branching fraction of this decay is measured to be (2$\textit{.}$91 ± 0$\textit{.}$47 ± 0$\textit{.}$33) × 10 , where the first and second uncertainties are statistical and systematic, respectively. The ratio between and is determined to be 1$\textit{.}$05 ± 0$\textit{.}$23 ± 0$\textit{.}$14, which deviates from the isospin symmetry conservation predicted value of 0.5 by 2$\textit{.}$1$\textit{σ}$.