Hydrocarbyl substituted carboxylic compositions and derivatives thereof useful as dispersant/viscosity improvers for lubricating oil and fuel compositions. Carboxylic compositions are derived from (A) a hydrocarbon polymer having Mn ranging from about 20,000 to about 500,000, and (B) an α,β-unsaturated carboxylic compound prepared by reacting (1) an active methylene compound of the formula (I), and (2) a carbonyl compound of the general formula (II), wherein Ra is H or hydrocarbyl and Rb is a member of the group consisting of H, hydrocarbyl and (III), wherein each R' is independently R or OR and each R is, independently, H or a hydrocarbyl group; and lower alkyl acetals, ketals, hemiacetals and hemiketals of the carbonyl compound (2). Carboxylic derivative compositions are obtained by reacting the carboxylic compositions with a reactant selected from the group consisting of (a) amines characterized by the presence within their structure of at least one condensable H-N