Forming complex structures of functional materials in a controlled and reproducible fashion is a well-known challenge. Specifically, bimetallic phosphides are of interest as electrocatalysts for energy-related applications; however, a satisfactory structure-function relationship has not been fully deciphered yet. In this work, we show that a colloidal chemistry approach produces bimetallic phosphides of Co and Cu, where segregation and phase transformation induce significant changes in morphology compared to solid solutions. Their complexity permits the tuning of the catalytic sites to the hydrogen and oxygen evolution reactions (HER and OER), allowing the bimetallic phosphides to catalyze the full water splitting reaction and methanol oxidation reaction. The experimental results show that in alkaline medium water cleavage is particularly favorable on CuxCoyP catalysts (and especially when x = 50%), enhancing their HER performance with an overpotential of 184 mV @ 10 mA/cm2. As for the OER enhancement, the results show that the bimetallic phosphides undergo a surface transformation during the OER, whereby (oxy)hydroxides form at anodic potentials in alkaline solution and serve as the actual electrocatalysts. The best OER performance was displayed by Cu25Co75P having an overpotential of 283 mV @ 10 mA/cm2. Thus, the use of CuxCoy phosphides as starting materials can lead to optimized oxide growth resulting in better catalytic performance. The higher catalytic activity of the bimetallic phosphides is attributed to their altered morphology, surface area, adsorption sites, and valence state, which also make them efficient bifunctional electrocatalysts for the overall water-splitting reaction. Additionally, these CuxCoyP catalysts offer promising functionality towards methanol oxidation reaction (MOR) without fully oxidizing it to CO2 and rather producing beneficial by product of formate, displaying a lower overpotential by up to 160 mV as compared to OER and a higher mass activity. This kind of selective oxidation of methanol is highly desired in direct alcohol fuel cell applications.