plants_novice
I also suspect over watering, possibly combined with anaerobic sludge at the bottom of the pots. When was the last time they were repotted and what kind of potting mix was used? What kind of fertilizer do you use and how often? Both pots have drainage holes, right?
Also, could we get more pictures of the first plant (is that an epipremnum aureum, commonly called pothos?) showing the whole plant, especially the upper leaves? The new growth that I can see in that photo appears quite light-starved. Unless your plants are close to your floor to ceiling windows, they are getting less light than you might think. Indoor light intensity drops off quite a bit with every foot from the windows. That big yellow leaf on the front bottom could just be normal attrition.
