The crosstalk delay and frequency stability of MLGNR interconnects on dielectric materials with rough surfaces are investigated. Two interacting parallel interconnect lines (aggressor and victim) are considered. ABCD matrix model of two port networks is employed to obtain an equivalent single conductor (ESC) circuit model for decoupled victim line. The effect of substrate surface roughness is appropriately included in ESC model. The most common dielectric materials (SiO2, BN and SiC) are considered. By setting up a driver-interconnect-load (DIL) system the crosstalk delay and stability analysis of MLGNR and Cu interconnects are performed. Results show that the crosstalk delay and the stability of MLGNR interconnects oppositely response to the surface roughness of underlying dielectric material. Namely, dielectric materials with rougher surfaces translate to longer crosstalk delays while more stable systems. While MLGNR interconnects on SiO2 have longer crosstalk delay in compare to Cu counterpart, MLGNRs on BN and SiC have shorter crosstalk delay with respect to Cu ones. Therefore, to hold advantage of MLGNR interconnects on SiO2 over Cu counterpart either the SiO2 surface must be more precisely polished or MLGNRs with higher doping concentrations shall be used.