We propose a framework for bilinear multiplier operators defined via the (bivariate) spectral theorem. Under this framework, we prove Coifman-Meyer type multiplier theorems and fractional Leibniz rules. Our theory applies to bilinear multipliers associated with the discrete Laplacian on Z d , general bi-radial bilinear Dunkl multipliers, and to bilinear multipliers associated with the Jacobi expansions.